Other than it being wireless, what other advantages (for mobile/electronic devices in general) are there for Bluetooth audio?
I can't think of a single one. However i can think of a handful of disadvantages of Bluetooth for audio - range is limited to a few feet, limited bandwidth which in turn lowers audio quality, another device to charge and the (possibly) extra cable/charger needed for that, arguably bulkier (in some instances) etc.
Problem is, Bluetooth was never designed with audio quality in mind. Rather it was for headsets and small data transfers and overall, the protocol is a bit shoddy, bloaty and generally a mess - iRDA/"flinging poo at walls" springs to mind.
If there was a proper wireless audio protocol that could replicate audio bit for bit, then i'd be all for it but until then, Bluetooth is no way a replacement, (and shouldn't be seen as one) for a decent analogue output.