Arrangers are tools like a saw is used to cut wood for those who don't have teeth on the edges of their hands,,,,,and don't care to grow them.

Ever since I was 15 I would rather play music than "learn how to play" music. Would I be a better physical player with speedy chops in more than three scales? Definitely. With today's technology does it matter. not really. Transpose buttons are my friends.

Now intelligent arrangements have suddenly become my friends. I view them as tools to substitute for those I don't have in ny tool box to build the same house another can build who has all the tools...like my classically trained wife, She actually asks me how to play some improvisational scales. Of course I can only show her in CGEA+F....LOL

Forget about the black key scales, I only know the major ones there.