Hello AkMike,

That system is called Optimum Infaillible and was invented and patented by a French gunsmith/retailer who licensed it to us (Verney-Carron SA).

It is based on the fact that when you point at something, you extend your arm to have your index finger as far as possible from your eyes.
Following that reasoning, when you aim quickly at something as it is done in "battue hunting" it is easier and more natural to have the red dot as far as possible to just have to put it on your targeted game.
It was however necessary to have a light red dot sight such as the Docter (40g) or the Bed40 (55g) in order to prevent imbalance.
And the red dot sight is interchangeable with the classic metallic sight which can be useful if you encounter a problem with the red dot sight while on the hunt...

More info (unfortunately in French) at => Optimum Infaillible