Sometimes, a DM might want to do hidden dice rolls, such as for listen and spot, or any roll that represents noticing without consciously trying to notice. I think it's nice since it doesn't leave players wondering about what they missed, thus less ooc thinking. It's basically like DnD then where a DM rolls dice secretly.
I'm thinking the tool would be something like, what you'd use on an area, and the DM would select what should be rolled (what skill, ability check etc). Then a script would retrieve the rolls for him from all PCs in the area and see them all compiled in his log. So it'd also make things happen quicker, without having to wait for everyone to make their roll.
Thoughts?