Is there any issue with buying a card that was previously used for mining?
If used by a home user who didn't know what they were doing they might have run it hotter for much longer than a typical gamer so the thermal paste might need a redo.
If used by some miner doing it even quasi-professionally or as a side-gig I'd much prefer it over a 2nd hand card from any typical gamer (most miners) they've kept the voltage/temps low and taken care of it far better than a gamer who might be power cycling regularly and definitely thermal cycling even more regularly.
This is the actual answer to its own question 99% of the time, they gain a misguided sense of their own self-importance through survivorship bias.
Luckily we have people like Alex and Khabib who come along and - at least temporarily - humble the cunts.