curious to know what you would use this for?

local dns, static site hosting, local apt cache, various other network services (unifi controller if you've got those APs for example), remote/headless dev machine (maybe not for kernel or bigcorp java development), or whatever else you want. mail if you want. Anything :)

Those little thin clients aren't gonna be fast doing "big" things, but serving up a few dns packets or whatever to your local network is easy work and pretty useful.

I use it for media hosting. Backups (connected USB disks), home assistant, syncthing

Even these low-power CPU's are surprisingly capable. As an example of more fancy thing, one could slap in some external storage, install Jellyfin, and run their own local streaming service off such a machine. The CPU is modern enough for efficient hardware transcoding of a stream.