I have several, I use them for multiroom audio with snapcast (mostly with USB DACs although one has a DAC hat. Some have temp and humidity sensors, one has the rpi cam. One has a always on vpn connection and transmission running. For a while I used one with a Parsec client and cloud gaming. However, I use a Odroid XU4 for all the big stuff (home assistant, NAS, nodered, mopidy, etc.)