It doesn't really aid understanding, doesn't incorporate active recall, and tends to become inefficient for a large corpus of knowledge.
We deliberately have some, though. There's some stuff that's just helpful to memorize to be able to do more active work and understanding with (multiplication tables, basic chemical formulas, sets of trig identities). There's also some stuff inserted (poem memorization, latin & greek roots for one grade, all 50 states for another, etc) just to strengthen the skill of learning by rote for when it's useful later.
"Oh, I remember I saw something like that in school, let me Google it!"
Medicine, like law, involves a lot of memorization.
Also it's an ever changing field of course.
This seems like a good thing, not a bad thing.
I'd MUCH prefer to have a doctor verify a diagnosis with reference material than to have them rely on their memory.
Yes, it's useful to have that knowledge already, and to that I'd say that copying out a textbook is a poor way to learn. It's far better to know the processes behind things or to learn through experience.