For what it's worth, why does this have to be compulsory? The temporary ability to turn it off is welcome, but some of us work on laptops, so don't have acres of horizontal space to give up for this. The ability to add links to other apps is of no benefit to me personally as we currently still have shortcuts from the start button. I expect this will probably be removed soon...
This looks like a team trying to make Outlook the place you do all your work with native links to other applications. Within our specific work office environment, we now have both Teams and Outlook trying to be this kind of 'everything' app (and Office 365 via the browser tried to be something similar and hasn't entirely gone away).
The result, obviously, is that I currently have to keep across Outlook, Teams, Office 365 and Skype to keep on top of everything - I can't unilaterally opt out of any of them because different parts of the organisation use different ones for different things.