Layout and sketching is obvious why. For math it's the bit of extra "ram" you gain from effortlessly jotting something down and building visual helpers.
All this is aided by memorization not hindered. In my experience studying Physics not memorizing has slowed down my thinking while having the main concept in my brain has made certain problem go from "impossibile" to "trivial".
For me the possible boost in memorization on paper however does not outweigh my ability to re-structure (nested lists in an outliner) and edit text on the PC.
This is especially true if I need the information later again, because full-text search helps and a well structured document also let's me dive back in more easily. Here I also have the added benefit of not needing to digitize it before sharing it.
Optimize for things like understanding, structuring, throughput, tool assisted recall, efficiency...
I embrace "prosthetic knowledge" and think it does me a lot of good.