I have a Lena Blackburne. There was a time I was collecting Blackburne cards as I'm fascinated by his contribution to the game, which has lasted forever, and so I picked one up.
It's really a pretty cool card, and while I agree with Frank's assessment of the term "buyback," I also think it's an outstanding way to get younger collectors interested in vintage cards - so I'll give them a pass for poor grammar.
-Al