It's a little annoying, but it feels like the least annoying path with the least number of steps to me .

Pretty sure Rick nailed it. In the past, before using eBay postage I've had stuff returned or arrived to the buyer postage due when I put Do Not Bend or Non-Machinable stickers on them. They get dinged for the "package" rate as opposed to the "letter rate".

The size on that one isn't the issue, I send patches in 6x9 envelopes at the letter rate all the time with no problems. They are thin with one piece of cardboard in the package but also bendable.

I think it also matters where you drop the mail off too. I've had zero issues with anything like this since COVID and my carrier is picking up my outgoing mail. We have two different post offices in my are and one Postmaster seems to be a "by-the-book" kind of guy and the other doesn't care because every item I've had sent back was dropped off at that PO.

I find the size/shape rates absurd. For example for a similar size/weight package, one conforming to the 1/4 inch thickness, one not, probably traveling on the same vehicle and route if sent at the same time:

One card in a card save, plain white envelope, letter rate .55
One card in a card saver, eBay shipping .51
One card in a card saver, to Canada $1.20

One card in a card saver in a bubble mailer, package rate = $3.09 and up
One card in a card saver to Canada, package rate $14.09 and up

I print the shipping labels for my eBay PWEs on the same pre-gummed label forms (2 on an 8.5" x 11" sheet) that my wife and I use to ship First Class and Priority Mail packages for our other eBay sales. The only thing I do after I print a label is to quickly cut it to fit the size of the PWE I am using. I'm very happy with the eBay PWE feature, which I have used for about 40 shipments already.

Check Your eBay Invoices for Overcharges on Standard Env.
 

When looking for an item # on my February eBay invoice, I noticed that eBay overcharged me on seven different items when using their Standard Envelope feature. As you know, in late January they were having issues whereby if you hit print label, it sometimes generated a message "Unable to Generate a Label" so you would have to hit print label again. Every time you did this, you were being charged in my case $0.51. One item was charged 17 times instead of once - the others ranged anywhere from 2 - 6 times. Of course, eBay did not notify sellers of this so just spent two hours combing through the invoice and another 45 minutes on the phone with an eBay CSR trying to get credits back to my account. SO BEWARE and check your January and February invoices.

I have been using this new service for the past month and shipped out over 100 cards, only 1 wasn't delivered! I am pretty happy about this cost effective way to mail out 1-3 cards for under $1.

Did eBay agree to give you credit for these overcharges? I just checked my February eBay invoice and discovered that I was overcharged 8 times. The total $$ amount isn't much, but it pisses me off that eBay hasn't notified sellers and done corrections.

Just had my first ebay envelope lost. I did a search and the Postmaster contacted me and he had no idea of what I was talking about. He had never heard of a standard letter that could be scanned. He knew nothing about the ebay letter option . I see ebay has it scanned and it is scanned by a postal employee, but if you go to their website USPS.com, you can't track it, it's not in their system. The left hand doesn't know what the right hand is doing. What a system ? How can it be scanned by a postal worker and not be in their system ?

a postal employee can not scan these. the scans come from sorting centers.

kind of like how usps scans the mail for informed delivery.

I just now called eBay and spoke with 2 CSRs about this issue. The second CSR reviewed my invoices through March to date and determined that I had been overcharged 10 times for a total of $6.30 (pocket change, I realize). The CSR stated that I will receive a credit for the overcharges on my March invoice.

Also, I told the CSR that I was aware that other eBay sellers who were using the new Standard Envelope process had suffered similar overcharges on their eBay invoices, and I suggested that eBay might earn some positive kudos by taking the initiative to quickly identify all the other instances where this has occurred and issue credits to the affected eBay sellers. The CSR said she will issue a request for eBay's IT department to investigate this issue.

With the new tracking on ebay I have had one lost or missing item . So I issued a missing item search at USPS.com. The local postmaster contacted me and he know nothing about this new envelope option on ebay. Here is what I got back from him recently :
" I have reached out to District and they have heard nothing about this type of tracking.
This tracking number is not compatible with USPS tracking.
I think you should reach out to EBay and ask if there is an additional tracking number or information they can provide.
It appears there is some misinformation floating around. "

So USPS scans the item but it doesn't go into their system so they can't track it, but the data goes to ebay and the ebay seller/buyer . That is unbelievable to me.

tracking
 

These barcodes cannot be scanned by the clerks or the carriers. These are Intelligent Mail Bar-Codes that can only be read by the high speed sorting machines at the large processing plants. So, let's say that your envelope is mailed in Dodgeville, WI and heading to a small town in Illinois. It won't be tracked/scanned until it arrives at the Processing Plant in Milwaukee. Then, when it arrives at the Distribution Processing Plant in Chicago, it will be scanned/tracked, and then it will arrive at the small town in Illinois, where it won't be tracked or scanned.

eBay will see that this letter was scanned at the Plant in Chicago and is headed for small town Il. That is when eBay shows it as delivered. It should arrive at small town Il. on the same day that it was scanned in Chicago and be delivered that day. (Maybe-Maybe not :))

Remember, your local Post Office, your local clerks, and your carriers cannot scan this IMB. It is completely different than the barcodes that are used to track packages.

understood....... I guess that last step is when eBay considers it delivered,
although it appears that there is no actual scan at the final destination....has anyone had a card that was noted as "delivered" claim to have not been deliverd? seems inevitable........ which side would eBay take in that event? (probably rhetorical at this point..)

I recently purchased a card that apparently was shipped using this system. I didn't understand what the ESU tracking number was when I saw it. The tracking info shows a little differently than something shipped with regular USPS tracking. For instance, it doesn't show arrival at my local post office. Instead, the Out for Delivery status shows from the sorting facility that is usually the last stop before my local PO. However, the status in the tracking does show Delivered on the date and time my mail was delivered that day and I received the card.

tracking
 

Yes, that is all done through the magic of GPS and the expected delivery time that is determined by the scans of the carrier when he/she leaves the office. These are not actual scans of the letter.