Functionality:
Using grid view you could import a long PDF sideways while being able to scroll the howl document down. You could name, hide/collapse and do other actions on sections by having a menu on the left and right of the page. Names could be saved in the outline feature.

Use cases and benefits:
Grid view could be beneficial if you have a long PDF you import and want to make Notes on a separate page. You could split the screen, but this would be much more time-consuming.
It would also allow to skip a section of a document much faster. Organization would also be much easier by having the outline feature more accessible.
As a student your exercises could also be on one section and your wiki of information on another one. This would allow short access to the wiki, you might want to use only sometimes. Using split-screen you would have it open the howl time, wasting screen space.

I would really appreciate this feature and thank you for this great app.