I work in more applied fields. When I’m doing a long derivation, I draw figures and arrows and my notes spill over from my current view into a larger view.
I find the page concept limiting (for me). I scrawl something but I need an infinite canvas to relate multiple ideas (my mind doesn’t work so linearly). That’s when refresh rate matters a lot.
Also matters when skimming. Eink displays are not conducive to skimming over many pages. That problem is solved on LED displays and paper, but not epaper.
I'm a mathematician and my "creations" are small notes, comments, and very simple figures.
I've never (besides flipping pages) experienced any noticable lag or delay.