Except disguised such that people think it is not webmail. They are replacing a desktop IMAP client (which stored data locally) with a webapp that (it sounds like) copies all of your Google Mail to a Microsoft server.

I do think this is a big deal, certainly my expectation was that the New Outlook work alot like the old Mail app.

Do you use web based clients to access third party accounts?

This smells like clueless users wanting outlook on their phone without wanting to do any set up

This isn’t even true for every webmail.

Some run locally in the browser.

Many don’t send the credentials to be saved cloud-side.