What exactly does the Office 365 integration do. Is this just a widget to be added to courses, or...

Dylan.Barrett62

What exactly does the Office 365 integration do. Is this just a widget to be added to courses, or can it replace the course mail tool? How does it interact with the coursemail tool? From Classlsit can instructors still click "Mail class" which opens 365?
 

I'm looking to have a way for students to access information in fewer places. I suppose my main question is does this tool simply add a widget, or can it functionally replace the course mail tool in other places such as the classlist.