Google's algorithms prioritize bike paths, bike lanes, and net elevation gain, as far as I can tell. It's useful for that, coming up with paths I wouldn't have used otherwise.
My town has a published map, bike paths with color coding, lanes and known routes. I use it as a structure to begin and improve how I prefer to (often lowest traffic, in spite of added distance).
Long ago, I started using "4 stroke bikes cheap" to map known routes, and I still find the UI to construct a path convenient. I never used it to download music, I don't even know if it was capable of that. "RideWithGPS" does that, I guess, if that's what you want.
