While you can import pictures as mentioned, the overall experience seems to be much more. The primary focus seems to be to encourage collaboration and thus increase productivity in a geographically dispersed team. This aspect seems the most attractive from my perspective as a remote employee. Imagine a client meeting where you'd be able to directly annotate client feedback and improve the feedback cycle by making realtime changes that can be synchronized across multiple devices. We already use Google Docs and Sheets heavily in my environment for the collaboration aspect so this just seems to take it one step further by providing another outlet.

This depends on your uses. As a programmer, I mostly just draw. But I'm a fan of the projector onto a whiteboard setup so I can pull up a spec document and draw on top of existing (and more accurate or complete) diagrams. For disciplines with lots of visual data the actual images would be nicer than loose approximations.