You can make tutorials or show specific issues while explaining with video
Definitely useful. Does a simple pen tool work? Do you envision the drawings disappearing after certain amount of time or staying on screen?
I'm thinking something simpler, like a laser pointer, an arrow, a square or circle. Something you could tell the viewer what you're talking about. They can disappear with a keyboard command to continue the presentation. For example, I use this tool a lot and could give you some good ideas: https://technet.microsoft.com/en-us/sysinternals/zoomit.aspx