True, it's essentially an emulation not of the hardware but of the API. I was using it loosely, but the point is, hijacking Wine's already re-implemented API would be trivial given that limited verification are possible on it and hooking all critical Windows API functions is essentially trivial.
Not really a huge issue - professional cheat developers invest huge amounts of effort in subverting and patching the Windows kernel itself just to get a step ahead of anti-cheat. Thinking about how much fun that kind of thing is really makes me rethink my career choices...
https://www.winehq.org/about/