The concept seems nice, but I don't think I will get some anytime soon. Let's see the problems:

1. I use bar-end shifters
(and MTBs bar-ends don't fit on road bars, as it is not the same diametre) Besides, if I installed some, I'm not sure where I would put my hands.

2. They aren't effective if the handlebars aren't parallel to the ground (dixit above). Well, mine are aligned towards the rear hub (about 20 degrees down)

3. They aren't very bright compared to the Planet Bike blinker shown above... which is very weak compared to the Vistalite Super Nebula I use. And I use 2 of them near eachother in the city, more on the road (larger light surface means it's easier to see from far away).