It seems that way to us on the face of it but the lines that've been trotted out are firstly the worry that money is coming from an illegal source whether underaged or trafficked and secondly that money laundering could be happening, OF would be/is an extremely easy way to clean dirty money.
They used to have to set up actual businesses that did actual work in case a genuine customer appeared, now they can buy feet pics and jars of farts or whatever.
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.