I mainly use it for a lightning node, and nostr relay but you can keep all your own photos and documents on your own computer instead of "on the cloud" which really just means some corporations computer that spies on you and can lock you out at anytime.

nextcloud for local cloud file storage, jellyfin for media streaming, vaultwarden for password management...then tons of btc and nostr related stuff as well. im not super comftorable with command line linux ( although ive gotten better) and start9 just pushes that all to the background...simply click, install, use