Burning metalminds give you a burst of the stored attribute. Maybe burning a memory would give you a clearer, detailed memory? This would make sense for Lord Roller's memory.
Guys what if Shallan is a copper compounder whooaaaa crazy
And muscle memory isn't really a memory, more like an imprint. You'd have to manually learn skills, because those aren't conscious memories.
You could store technique, like instructions on how to swing a sword, but not skill, like actually swinging the sword.