Stardew Valley might not the best example as it was designed to work also with a gamepad. You control the mouse cursor with the right analog stick and the player with the left stick.
Ah, well. I've been playing a lot of it lately. Its the same with the steam controller except the touchpad is a really nice mouse.
The steam controller probably should still work well in scenerioes where a controller is intended. Admittedly, I don't think it's as good for third person games.
