I was thinking about getting a graphical drawing tablet, but I'm worried it is just a gimmick. And all reviews are from artists anyway.
Do you have a similar setup? What combination of hardware and software do you use?
Depending on the software, the pressure-sensitivity might not work so well, but that shouldn't be an issue for whiteboard-style usage.
My recommendation is that you use a 60% or tenkeyless keyboard so that you can comfortably fit the drawing tablet to the far side of your mouse on the desk and still be able to type. Having a trackball is nice since it means that you don't have to give yourself a large area in which to use the mouse. If you're ambidextrous with the mouse, this won't be an issue.