Before the Xbox 360 arrived in 2006, using a gamepad on PC was a pretty annoying experience. You'd have to manually configure buttons, games wouldn't detect the controller or show the correct icons, ...

TL;DR: Microsoft's new Xbox Fullscreen Experience app, designed for handheld Windows 11 25H2 gaming PCs, optimizes system resources by disabling non-gaming functions, freeing up about 1GB of RAM.