Not a Slack user here. Is the app version _slower_ than the website? I assumed that since Electron is only a little bit more than a Chromium wrapper that they would have identical performance.
One Chromium runtime managing five tabs is more efficient than five Chromium runtimes running one site each (because those instances aren't able to share anything with one another).
Long time slack app user here, I don’t know how you guys organize your slack but performance has never been an issue for our organization, I don’t think it would run any better then it currently does if it were an os native app, of course my machine isn’t a toaster.
