Thing is, GameStop is, well, for videogames and videogame paraphernalia. It's not a general store. Doing this would turn them into a thrift shop, not a pawn shop, as people are trying to offload their carpets, desks, etc - bulky stuff.
I don't think this makes sense.
This does make sense when you consider the collectable market, another domain I'm involved in. Trading card games, specifically pokemon, have exploded over the last 5 years. GameStop is making a killing off of buying, selling, and grading these cards. Ebay is the primary marketplace to buy and sell those cards. There's also tax free havens ("Vaults") offered by multiple companies, grading service passthroughs, and scalping offered through ebay too.
Viewed through the above lens, that's what's prompting this offer, I think.