This isn't a new idea, in fact many other users have previously voiced their interest in having the ability to play their whole music collection (including local files) on their favourite platforms.
You see; Spotify isn't just a collection of tracks, it's many people's preferred service for not only finding great music, but also getting the most out of the listening experience.
Spotify's Connect technology already allows us to listen on a vast array of devices, and encourages developers to build functionality into their products.
I love that such technology exists, it makes listening to my favourite music through my TV/AV receiver possible, but I feel that this could be improved by allowing local file streaming in addition.
Updated on 2019-10-27
Hey and thanks for bringing your feedback to the Idea Exchange. We've marked this as a new idea.
Spotify Staff will look into this idea once it reaches the necessary amount of votes.
More information about how the Spotify Idea Exchange works can be found here.