Oh no no no, that is not my experience at all! Only few games where seeing steam controller as a gaming pad and only the native steam games.
I tried to play fifa 2018 and many other sport games adding them to steam as a non steam games and I couldn't make steam pad work.
My xbox controller is just plug and play and all the games see it and I play comfortably.
Okay, maybe I am doing something wrong, I was even trying this GloSC or whatever the name was but without success.
Sometimes some extra finagling is required to make it show up in some non-steam games, like having to manually select the controller in the game's options menu, making sure it's the primary controller in its steam-side controller settings, or sometimes even setting steam input to 'forced on' in its big picture page. It also won't work if the game's exe is set to run as admin (for whatever reason) but steam's isn't.
Making sure to unplug other controllers can help as well, since they might be getting picked as 'device 0' instead of the steam controller.
I've never had to use GloSC myself, though it seems like more of a convenience thing to sidestep the requirement of adding stuff as a non-steam game. It won't help if the game is already having trouble picking it up for whatever reason.
A lot of exclamation points flying around in here. I'm a little uncomfortable.
Anyway, I always thought the Steam controller looked like a solution to a problem that doesn't exist. Mouse and keyboard = good. Traditional joypad = good. Weird hybrid = not so good.
Never tried one, though, so I could be humongously wrong.
In theory it can give you the optimal setup that is analog stick movement + gyro/mouse aiming (plus whatever fancy shortcuts you can dream up with steam's input action system), but in practice it depends on the game.
Some titles refuse to take KB/M and pad input simultaneously, some will rapidly flicker their UI prompts back and forth, some (older) titles are designed for DirectInput only and won't take analog input, etc etc.
It can be a crapshoot, but it's great when it works.
Steam controller looks really ugly and uncomfortable
It needed a second hardware revision with nicer ergonomics and a real d-pad to truly shine tbh, but it's still good despite the flaws.