Building on Ryan’s point, which was posted last night as I was typing my reply - if you start adding game cards with no photograph on them, you’d basically open yourself up to Monopoly cards, Trivial Pursuit cards, etc. And sure, while most people would say no, those aren’t trading cards, you’d find several folks who would look at some trivia cards and say “hey, these mention [player x], why can’t they be listed?”
By all means, collect them. But there has to be a line drawn for the site somewhere, and this is where Admin has chosen to do so.
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.