"Every perception is to some degree an act of creation, and every act of memory is to some degree an act of imagination."
-- Gerald Edelman, Second Nature: Brain Science and Human Knowledge
5 How important is memory, anyway？7 How important is memory, anyway？How important is memory, anyway？How can we develop transformative tools for thought？2020-10-18Journal
But the truths of the last paragraph also have limits. If you're learning French, but don't know any French speakers, then waiting for “natural opportunities” to speak just won't work. And even if you do have (or create) opportunities to speak, it's desirable to accelerate the awkward, uncomfortable early stages that form such a barrier to using the language.
It's in this phase that memory systems shine. They can accelerate people through the awkward early stages of learning a subject. Ideally, they'll support and enable work on creative projects. For this to work well takes good heuristics for what any given person should commit to memory; what is good for one person to memorize may be bad for another. Working such heuristics out is an ongoing challenge in the design of memory systems.