>> Is it supposed to?
No, but those tools should be corrected to recognize edges/faces within groups independent of deep select.

>>If not, what is it good for?

We orginally put it in to select objects within groups. We're gradually extending its functionality. Things that deep select can do

--modify objects position/attributes within a group
--automtically turns on/off points &handles for splines
--pick faces of a solid and change color
--pick faces of a solid and remove them by hitting the delete key


Tim