There is often a need to draw on a whiteboard. This is still a key area for classrooms and meetings.

In a channel, it could be very useful to allow multiple whiteboards. This way a person can draw something out, and leave it (the "Do Not Erase" model in real conference rooms). But then also allow others to add/modify/comment, etc.

Skype for Business fell way short, as whiteboard does not function for Mac OS.

Whiteboard app on MS Hub will release for Win 10, but no verdict on support in Teams or Mac OS.