Very useful. It helps speed up and automate a lot of tasks in Aseprite that are a bit cumbersome (like setting up the grid/checkerboard, or expanding the canvas). Instead of having to input pixel numbers manually, you can just hit a button!

And the way you can "fold" down the toolbar using the check-boxes is very clever, and makes sure that the toolbar is never cluttering your workspace. The Info check-box makes a detailed help screen popup, and every option is explained clearly.

I definitely have this toolbar open all the time now. It's a must have, for sure.