This is especially helpful for interactive web sites and programs, or when the teacher wants to simultaneously interact with students. Software examples to use would include Starfall or BrainPop. An adventurous teacher could even allow students to take turns using the Mobi.
There is a slight hand/eye coordination required as the pen and tablet roughly translate to the screen. I also found that it was easier to rest the hand on the tablet. Since only the pen registers, there is no interference with other things touching the tablet.