It is very effective for me, I can play multiplayer fps games against mouse and keyboard players fine and honestly I enjoy it more than mouse and keyboard, probably because I grew up playing xbox/consoles (not that I find it difficult to use a mouse and keyboard, just not as fun) but also because it just feels like I am aiming so snap shots and things are wayyyy more satisfying to me than if I just moved a mouse to click on them.

In practice it isn’t necessarily easy to tell I am using gyro except for when I do brief quick reaction shots just relying on gyro for aim, the rest of the time I don’t ever think about using the gyro consciously, I just used the joysticks for rough aim and let my brain figure it out with the gyro to lock my joystick aim in. Recoil in FPS games is also way more fun to control with gyro, it is a more direct control relationship rather than dragging a mouse down a mousepad for me.

I don’t move the Steam Deck much though, it isn’t like I am getting a work out whipping the Steam Deck around, the gyro is really just there to lock in broad joystick movements to be accurate and on target consistently without the small aim adjustment problem that joystick deadzones create.