Yes, memory is a necessary but not sufficient component of learning. "Piano playing" seems like a really poor example to argue against the value of memorization.
The post I was responding to said "Memorization is the same as knowing". I specifically chose a counterexample to suggest that knowledge is deeper than memorizing some facts about the world.
In fact, I would argue that most of the forms of knowledge that are truly valuable are exactly the kinds that aren't amenable to memorization. Think about any skill that's in high demand and takes decades to master. You're not going to get there by studying Anki cards.
Do you think it's possible that knowing more information that is amenable to memorization will help you cultivate knowledge that isn't amenable to memorization better or faster?
At some point in our education we have to memorize the rules for manipulating algebraic formulas, trigonometric identities, etc. It would be hard to learn calculus without being able to do these things unconsciously.
On the other hand, what a professional mathematician does is create new tools for proving theorems. This can't be memorized because, by definition, the knowledge didn't exist. It's true that they draw on previous experience having solved similar problems. But it's not clear to me that this knowledge is most efficiently gotten by drilling the same problems over and over.
I think this idea of using Anki for learning everything is misguided because it attempts to reduce complex topics and pragmatic know-how to a set of trivia questions. An example from the article: the author wanted to understand the AlphaGo paper, and some example flashcards were "who plays first in Go" and "where did AlphaGo get its training data". They probably could have acquired a much deeper understanding by playing a few games of Go and implementing a reinforcement learning algorithm for tic-tac-toe. Incidentally, that also sounds a lot more fun and motivating to me than studying flashcards.
Learning to play a song or to play from sheet music is, itself, a task that is well suited for rote learning. There's really no way out of repetitive practice if your goal is to learn to play a musical instrument.
