In addition to betting patterns/leaks, I have found the notes to be very useful to help flag/remember unusual hand ranges for future use.

For instance, couple I remember noting last night:

"Villain called AI PF 80xbb shove with A9s"
or "Villain raised 10xbb in BB on top of 4 limpers with 72o"

Note: Villain stacked SB (AJo) on that latter hand when 22J hit the board