You're right. I expect that they're reconciling with their model in JS on every keystroke. I know Quill does an interesting thing where the DOM is the canonical model, and the JSON model is actually derived from the DOM by a strict transformation. Because of that, it works a bit more naturally with many native mobile editor interfaces.
Re:Editor.js – Block Styled Editor
by oatmealsnap on Tuesday April 02, 2019 @10:45PM
(#19560356)
Yea, it was even causing my keyboard to lag. Keystroke queued up, but the key press state (enlarged visible letter above your finger) was really delayed.
Otherwise I love the idea of block-based editor and clean output.