I have two. The main reason I love them is I can leave them on all the time using very little power. Our would be surprised how much u can supercharge your home network by having always-on Linux boxes on it.

One runs nextcloud and serves as a nas. I use freeddns to give my nextcloud instance a legit URL for free. I use letsencrypt to host my cloud over https, again for free. The other runs emulationstation, deluge (torrent) which only runs when the box is connected to a VPN running on a vps, and serves up my movies and shows via minidlna.

I've also got some cool chron jobs that backup important stuff ((encrypted of course) to Google cloud and do some other things. I also serve up a keepass password database via webdav and do some neat stuff regarding keeping my keyfile separate fr my internet facing box but I won't get into exactly how that works.