You've selected some use cases designed to show that VSCode is inferior to emacs. What you failed to realize is that your use cases are invalid for probably a vast majority of people:
> Read, write and send emails
I prefer to do that in a dedicated app that actually knows how to deal with emails, and not from inside my text editor/IDE
> can I quickly write something that will read an email, and then go and add a TODO in the appropriate section of some document based on the contents of that email
I tend to prefer not to spend my time programming things, but, you know, enjoy life.
If I need a todo from an email, I'll copy paste it to an app that, for example, syncs to my phone
> Use it as a window manager
Why?
> Use it as a file manager
Why?