These devices are apparently already used for cheating. Here are some blog posts from Riot Games and ESEA mentioning direct memory access devices as cheating vectors and preventative methods if you are interested. https://blog.esea.net/esea-hardware-cheats/ https://euw.leagueoflegends.com/en-gb/news/dev/dev-null-anti...

Not really.

A few of the better anti-cheat products have had detection vectors for these for a while now, from simple things like detecting the driver to outright probing the device.

I would imagine it's no more "change everything" than having root access to your own hardware.