One use case would be a little desktop robot for an educational setting. The motors of a robot use orders of magnitude more power than the CPU so it needs big batteries anyway.
I can also imagine applications where the device has wall power but you want to connect to it with a phone. Like a piece of wall art you want to be able to turn on and off remotely.
I can also imagine applications where the device has wall power but you want to connect to it with a phone. Like a piece of wall art you want to be able to turn on and off remotely.