His purple-ness is also a ridiculously good guitar player in more styles than you can shake a stick at.
I place the musicality there on the OTHER guitarist, Prince was basically just strummin' chords.
A typical situation, really, where the Session Man, the Journeyman Musician who has worked and studied can take a chord change and work the embellishment, add extensions, runs and riffs, sometimes even create the musical hooks, etc. to what would otherwise sound like what it really is, a folk song sung by a good singer, accompanied by that singer's strummed chords.
IMO both types are typically necessary - but not always utilized well - and occasionally we will find one individual who an cover both tasks well.
--Mac