Yes, it is included in O365 and it makes it a no-brainer as far as additional costs and things go. But then there's the risk that Microsoft leverage their captive and lazy market to foist other undesirable things on users... like this. And crappy news / adverts in Windows 11's 'start menu' replacement.
Ready to get voted down on this, but my view is pretty robust: no need to self-host EVERYTHING but avoiding vendor lock-in and maintaining independence is valuable. It is a lesson that corporate IT admins seem to forget time and time again.