I am not so sure about emacs, could be plugins though. Disclaimer: I hate electron apps.

Definitely the plugins in your Emacs. Might want to take a look through them and clean things up.

Maybe for you.

None of your alternatives have built in JavaScript debugging or multiple projects per workspace.

I was replying to the performance of the application.

Debugging: Fair enough. VSCode is starting to stray toward IDE, which the others described specifically exclude. They focus on the text editing and leave the debugging for other specialized programs. VSCode would make sense to be an IDE since it's coming from a Visual Studio lineage though.

Multiple Projects per Workspace: Sublime has this as a project can have any number of folders added to it. A sublime project is equivalent to a VSCode Workspace unless I'm missing a nuance somewhere. Vim and Emacs are less useful in this regard, though they have project management plugins. Most of the time, Vim and Emacs will just save off a workspace in what they call a "session". You can load the session and be exactly where you left off (down to the cursor position). These can also be configured to happen on startup/shutdown.

I think he is referring to performance, which in my experience is true. You would have to do a really terrible job for an electron-based app to beat your native app performance-wise.