The most common thing I’ve seen are projects where it acts like a screen or control panel on the wall. Something that’s a fixture or art project.
You don’t need it for anything like music or games - your new phone will be more convenient and run those things better anyway.
A friend of mine stuck an old tablet on the wall and connected it via Bluetooth to his keg system. It gave him a permanent status readout on his beer temperature and how much was left in each keg. It just had a power cable plugged in all the time so it didn’t need to be charged.