Not just music history, but history in general. History told forwards is superstition: trying to show that what came after was inevitable, when in fact it was one future among an infinite number of different possible futures. History told backwards makes sense: look for the seeds of post events, in the past. However the human mind loves nothing more than causation; we see cause and effect everywhere even where it's n…
While history forwards is..."here's some stuff, it'll all make sense in a few years if you keep studying".
Understanding how we've arrived here, and all the connections going backwards can be profoundly enlightening, allowing you to try to project events forwards, because cause and effect are laid out for you.
Memorizing books full of facts just turns you into an encyclopedia and don't really let you try to understand how to break the present down to get at what the driving forces are behind the now.