Cool, maybe this means they'll finally be able to afford to implement the ability to play through a non-default sound device on Windows. You know, like the USB DACs a lot of music lovers have.
Sure, I could change the default every time I fire up Spotify, but that's annoying and I really shouldn't have to do it -- this kind of setup is not that unusual for music lovers, and it's not a difficult feature to add.
It lets you set an app to use a default audio device, which may solve your issue with spotify. Some apps just ignore it, and only play through the system default though.