You can gain in your effectiveness as a politician from a wide acquaintance with the world and from a degree of independence that having some outside interests gives. ↗
If a musician wants to be an actor, everyone thinks that's pretty cool. But if an actor wants to play a song, even if they've been doing it for 40 years, that's bad news. ↗
There is an apprenticeship system in jazz. You teach the young ones. So even if the musicians weren't personally that likable, they felt an obligation to help the younger musicians. ↗