It doesn't have pleasant soft edges such as can be done in Photoshop. And since the physical minis won't interact with MapTool's topology, there's really not much need for it.

On the other hand, I find it useful to be able to see the unobscured map on the PC monitor, where the displayed map has all the interface hidden.

edit: And I remain the Page Break King. The antecedant of "it" is MapTool's fog of war, for those who don't feel like clicking back to the previous page.