Low latency definitely makes for a better experience, but since it's javascript running the browser, I assume typing into the editor textarea and most features will go as fast as javascript will go.
Do you type faster than what javascript is able to handle?
Depends on how much JS is trying to handle.
I think you’re forgetting that javascript in this context needs to be constantly re-evaluating the whole document; It must do this for syntax highlighting alone, not to mention other plugins, spell checkers and auto-completes
but since most editors are also just electron apps, it's not much of a difference