I am only a rookie collector, but for me, I can simply go onto Ebay and find plenty of cool HOF with common backs that are just lovely, but when I want a rare back, I have to be verrrrrry patient and when I finally do land one, it is very rewarding and exciting.
I guess it is the thrill of the chase, so to speak. The rare backs just add this entirely different element that I absolutely love.
I just wish I had collected these when I was younger, because the prices today can be similar to a swift kick in the groin.
Totally worth it though