I don't collect T206s exclusively, but I do have more of them than any other prewar set. And they're not even my favorite prewar set.
So why do I collect them?
I think a lot of it is part of an early hobby experience.
1977 I moved to Arlington Mass from a place that was a bit small and backwards. 74 had been my first year of really buying cards and the Hank Aaron specials showing 4 of his earlier cards on each one fascinated me. I'd only found one older card, a 1968 that a kid traded to me from his brothers collection.
New town, Arlington, about 10x the population of the old place, which was a suburb of a place about as big as Arlington. After cross country practice I asked someone if they knew any places that had stamps/coins or old baseball cards. There was actually a place right in town! And nearly on my way home!
Going into Halls Nostalgia that first time was amazing. Old Topps cards in quantity. Boxes full of them. Some bigger than usual, who knew the HA specials had made them all look the same size. AND some funny small cards that were drawings. Bowmans they called them.
And there in the display case and some displayed on the wall next to it were the most amazing yet! Small and skinny, most displayed in a plastic pocket on a 3x5 with some stats typed on it.
Much prettier than the Bowmans, many of the players were shown against sunsets or in formal portraits that even painted had an air of importance.
I think I was hooked right then. I had to have one. But $1.50! for someone I'd never heard of.......I think my allowance was $2-3 a week. So they were expensive.
A while later they said they'd found a cheap one for me.(I'd been hanging out there after school maybe 2-3 days a week no doubt making them crazy with questions) Beckley, with a polar bear back. And a lot of tape holding the tear together that otherwise would have meant it was two half cards. But it was only twenty cents.

About a year later I got my first job practically next door. And I could actually afford some commons. I tried to get one of each brand back, missing by the usual suspects, but getting close.
Part of what keeps me interested is the stuff some people don't like. The big puzzle of just how they were made. That aspect can be tedious and dull and if you can't stand it, that's fine. I like the sunset cards, others like the portraits. Also fine.
For many sets that puzzle aspect is missing or so far beyond my means that I just can't get into it. I like 33 Goudeys, but there are complets uncut sheets, so not many mysteries.
I also like the stuff like caramel cards, and the tougher T sets. But a red cross or pirate is probably well over my budget. I'm sure there are mysteries about those sets, but I'll probably never own one or if I'm lucky maybe one of each. Hard to study when you don't own any and they're available seldom enough that even finding scans is a challenge.
Steve B