For artists it goes to the question of what you get for using a permissive license like CC. People are going to remix and repost your stuff no matter what, even without permission, so what do you stand to gain from saying it’s ok?

The one big thing that artists do stand to gain is that being a decent kind of dude helps create a friendly relationship with listeners. But you could get that vibe benefit just as easily by working at a soup kitchen (on-camera).