This is interesting and reminds me of the idea of “thinking in action” where insights/understanding happens while interacting with the concrete subject matter in exploration, experimentation, etc., which seems to be exactly what the author described she was doing when learning Russian or physics equations.
I don’t think that from “dull” memorization and mindless practice alone (how it was often done in school) understanding at a deeper level somehow magically happens. What I do believe is that both (“smart”) memorization and explorative/playful interaction with the subject matter (turning it upside down, interrogating it, relating it in different ways, etc.) support each other, which, after some time, creates enough structure in ones neural pathways such that deeper insight can emerge from intuition.
When we try to learn math conceptually, we focus a lot on metaphorical or contextual understanding (“what is this like?”, “how does this apply to the real world?”, etc.), which may divert attention away from the actual subject matter, which is the symbols, formulas, equations, axioms, theorems, diagrams and so on. It is all one really needs to understand.
Sometimes I read texts where the author talks about mathematical ideas in a very vague and abstract language, mystifying and obscuring it or entangling it with other subjects. But then it turns out what they write makes no actual sense in the language of mathematics, which itself is very concrete and clear. Maybe they have fallen into the trap of thinking that they knew about the subject when all they have is a broad conceptual perspective without any grounding in the actual rules of the formal system.