They are powered by fans "just because

This is the best kind of powering!

A buddy of mine had a 3rd party (or it might have been official) joystick controller for the PS4 and it was huge and expensive. It was meant to simulate the arcade experience for SF2 only but obviously it could be used for other games as well.

Needless to say this particular friend of mine was extremely good at SF2 as anyone with a $200 controller probably would be :)