Why use Google Draw rather than other mind mapping tools? Google Draw is collaborative and is in my Google Drive with the rest of my files, thus easy to find. Teachers can also insert comments on a Google Draw as you can in other Google Docs, so it makes for a nice tool for being able to give feedback.
I want to note that I inserted the above mind map BEFORE I finished it. I was able to File->Publish to the web and insert the embed code right here in my WordPress blog. As I make updates, my blog will automatically update, assuming the viewer refreshes the page. This is an advantage for students as we want to give them a low risk of failure. If they were to submit their mind map and then update it based on teacher/peer feedback, the map would not need to be resubmitted.
In a nutshell, Google Draw is a basic drawing program. You can check my blog for several posts on how to create Google Drawings.
Here is a quick video on how I use the connectors feature in Google Draw to create lines or arrows to shapes I drew that will move with the shape when I move the object.