I'd not be worried about wear but about whatever meddling was done with the firmware (edit: or hardware). Maybe an experienced miner knows how to easily return

I'd not be worried about wear but about whatever meddling was done with the firmware (edit: or hardware). Maybe an experienced miner knows how to easily return it back to stock, but who knows who you're dealing with. Someone else can take the chance. Also, PC gamers are the last group I would expect to successfully boycott something. They'll install some spyware-ridden game launcher just to get a $5 discount on a game, while complaining about it. What discount will they resist for a mined-on GPU? $50? Assuming they even know it was mined on.