I love reading the lyrics along to music. As of now, I have to open a lyric site separately to read along as I listen. This doesn't happen when listening on my mobile, which is the majority of the time I'm listening.
I think this would be a great feature for Premium Spotify users. Could create some new jobs, too.
I think it would be understood the majority of the Spotify community that some artists would not have lyrics if they weren't available, perhaps if it's a growing artist and they did not contribute when providing their music to Spotify (not sure how this process works anyway). In this case, I think the fans of the artist could contribute to then be verified by Spotify.
Good idea. By the way, in the newest version of the desktop Spotify, there's a button that says lyrics (it's near the bottom). If you click that, it automatically brings the lyrics up inside of Spotify.