The Steam controller doesn't have Hall effect sticks; they're TMR. Also, my 8bitdo controller does need special software to use a couple buttons on it. And it's the cheapest possible model, not a super advanced one. It just has more buttons than xinput supports.

This isn't to say that you're wrong about your main point. Steam is heavyweight to use just as an input profile selector at application launch. But you should be careful about details if you choose to include them.