If you extend that, then is music on your phone also an input and should it appear as an input alongside phono, optical etc too?
What do you mean by 'music on your phone'?
If you mean the streaming services on your phone, they have the wi-fi input.
If you're talking about music stored on your phone, sent to your WiiM, then that's the Bluetooth input.
Forgive me, I've not used these in a while.
But I return to the point, in hi-fi the terms 'input', 'source' and 'source select' are used fairly interchangeably.
Go back to old integrated amps, you flipped a switch to select record deck, tape, CD, tuner. If you have something you want to listen to, that's a source. If you want to decide which source to listen to, you use 'source select' or 'input'.
Arguing that something is out there, and you want to listen to it, but it's not an 'input' is, as I've noted, complete semantics.