Some more things I’ve used old netbooks for:
Portable pxe boot server
Audio source for mixing (think using a mixing board to do audio collage work with tape, record and digital sources)
Midi sequencer- the cheap usb to midi breakout cable works good here and you really don’t need much horsepower to sequence midi.
Tracker playback and editing
Display driver/art/digital photo collage/digital signage/whatever.
E: People will tell you that you’re better off with a sbc because it’ll save you money on power. Do your own research on this. A kill-a-watt is cheap and the power savings quickly gets murky.
it is?