In my experience, floor presses with a close grip was probably the best tricep builder ( both size and strength ) for me then any othr exercise. Never got the same results with a full range close grip bench.
I never tried floor presses with a meduim or wide grip so don;t know how they would have benefited me.
I dont think they have a benchmark purpose for bodybuilding simply because the ROM is partial. I do feel, however, that they are an awesome assistance exercise to boost your bench press, which will in turn help you press more and build more muscle.
"It`s fighting through those times of adversity and personal problems and still doing what we have to do, that seperates us from the average couch potato." - Tim