Outlook in Android work profile already requires device admin app permission, so it does make sense. A lot of people don't like using e-mail on phones, so I guess Authenticator won't go away.
I'm not sure if I understood you, but I believe this is more about that people don't want to use some other authenticator app for 2FA. So now Outlook will have a built-in authenticator, I would love to see something like this in browsers, I believe it would lead more people to adopt 2FA. It's too much of a hassle at the moment.
