It depends what your needs are. I only even listen to my collection of music from my NAS via (W)LAN connected devices, so maintaining a version more suited to mobile devices isn't necessary or useful to me.
Sure, if that works for you, but my collection is too big to fit on my mobile device (even after encoding it in Opus instead of FLAC).
I suppose my use case is rather rare, but even then, why not give the ability?