Ah.. I see. They look exactly like a set of combined brake/shifter units. My mistake.

So your point was more about them being below rather than above the bar, as with thumbies. Sure.. that helps, if one only has that position to work with but the point about thumbies being able to sit elsewhere still applies. Have you ever seen your style of shifter positioned anywhere other than right next to the brake lever. I can't say I have. Partly why I assumed they were integrated/combined as one.