I use it for sync’ing:

-Save file for non-Steam games, between my PC and Steamdeck.

-Sideloaded mods (Rimworld, Darkest Dungeon and emulated Nintendo Switch games), between my PC and Steamdeck.

-Anytime I want to quickly send/receive some files between my PC and Steamdeck.

-Lust provoking images from my phone to PC.