Hmmm... since VSCode is based on Electron/Chrome, it means that Chrome itself could be a webapp, and I could browse the internet using a Chrome instance that I have opened in Firefox?
The native VSCode uses Electron/Chrome, but the web version of VSCode is (almost) the same frontend (HTML/JS) rendered with your browser instead of Electron/Chrome
I don't think that VSCode is bringing its own Chromium runtime when it is running as web application... (it's also not the 'complete' VSCode experience because it can only install extensions that are 'web compatible').
The only reason you have a vscode desktop app is because vscode is just plain old javascript and will work with whatever html runtime. Chromium or webkit. It has nothing to do with electron.