Interesting..... I would have figured the French would have been more inclined to incorporate such "fashion" into their little "fu fu"pistols.
I found it strange on the Luger since it appears to allow the trigger finger to "reset" the trigger if it failed to do so on its own... but seeing as the Luger has no "second strike" capability it would seem to be a useless attribute in those regards.
Unless..... due to the tight nature of the pistol and its disdain for dust and debris, it was thought to help move the trigger back and forth and hopefully knock free any trapped battlefield "gunk."
I can see the Germans thinking in this respect....