Temporary memory is very limited and you'll constantly get distracted if you don't Close open loops
Externalizing your thinking also helps to ensure that you can pick up the task you've been working on in the future with minimal loss of context.
For me personally this mostly means writing things down (outliners are especially good)
I find visual media less helpful in most cases (Muse app or pen and paper didn't really click for me so far..)
Which seem interesting, given that many people find visuals really helpful 🤔