I thought the same thing, but per it’s suggestion I tried using it for fine tuning on the steam deck and I was pleasantly surprised. I’d never use it for for large motions, but on a game designed with mouse motion in mind it can be a little tricky to get those fine motions locked in.
I tried with portal and it made it a lot easier to get little adjustments lined up that were tricky without it. Since it exclusively kicked in when I wanted it to it wasn’t as wacky as a lot of gyro controls are for games that focus on them, and I think it was as simple as “press your thumb a bit more roundly onto the joystick”.

It’s not going to supplant the mouse for fast precise motions, but it at least means you can skip the wild overcorrection that sometimes happens with joystick on unoptimized configurations.