Well, a lot of the work on playing the tune as one wants to may come after having a got a set of notes, and what one wants to do may evolve during that. I just don't see why one would play a set of notes in the first place without having an idea what they were supposed to sound like within the tradition that they come from.

But then I'm coming at it from a "can read music but it helps if I know the tune" angle. (I'll leave attribution of the quote to others in case I have it wrong)