It's my understanding that since each app is shipping with its own Electron version/runtime, that the resources of these are not and can't be shared or managed centrally. A chromeless web app running via the browser would effectively be just another tab use the current browser's resources (and extensions +1).

Agreed. Sorry, I took your previous comment as arguing against the comment it was in reply to.

I was quite keen on chrome apps, as they allowed you to share the chrome browser runtime in a similar way. If you add a native desktop shortcut, and use the chrome-hiding features then you can basically replace electron with a shared runtime. I have a dim memory that it may have been killed/hobbled now though...