This is a natural step now that Spotify provides CD quality streams. Prior to that, having bit perfect was not a big deal. But with lossless CD quality it makes sense that they would add exclusive mode as an option.
The downside is that any other apps cannot be heard on the same output when Spotify is in exclusive mode. Some people like to have other apps able to also play, like for announcements. If you want that, you cannot use exclusive mode.
One question is what does it take for Spotify to release exclusive mode? Does it release exclusive mode when output is paused? Or do you need to go into settings to toggle it off or even exit the app? It should release on pause and regain it on play. Just something to be aware of if you want other apps to be heard.