If I was doing accounting I would pull out a tenkey board, but I often find myself typing phone numbers, machine coordinates, etc, that require more than just a couple numbers, along with +/- and decimals, so what I do is move all fingers up to the numbers like they would be if they were on the home row.
The problem the home bumps would solve is when I have to move my hand over to hit backspace, shift, or enter. Finding my way back to the correct numbers is not all that easy. I'm using the Nuclear Data numpad keys as the number row on one of my keyboards, and the homing 5 gave me this idea.
With sculptured keys, this wouldn't be possible, since I don't think the bump is available on other rows, but since this set is all row 3, we can make any key have a bump. Braille keyboard anyone?