I remember people clowning on the Steam controller at the time, but I used it for many games (having to, at the time, manually map the controller inputs) and it was perfect for me. The dual trackpads that I could map to become radial controls, touch controls, whatever I wanted was awesome (I was really in to Elite: Dangerous at the time). I think a lot of gamers just don't have the time or motivation to tinker and customize the thing for themselves. Also, a lot of games didn't handle the Steam Controller's rapid input doubling/switching between mouse and gamepad.