I think as much as versatility is important, a defined and polished sound has to exsist.
Basically, what I'm saying is, you should be able to do a convincing equivalent to what is respected in the genre for any sound you attempt to tackle. If your symphony scores, trap beats, progressive rock, RnB, and EDM all sound like they came from the same casio keyboard...you're better off just having 1 style that sounds authentic. Same time...you wanna get to a place where everything you do in any genre across the board sounds authentic.
Alot of 1 man bands fall short to this because they overlook key elements to making convincing music in the genres they attempt to tackle. Mixing and sound selection is an essential key.