Why is it that in all the Payseur digs, nobody ever mentions that the original French spelling of the name in France was Pesour?

This is an older French spelling of Peseur which means weigher and refers to someone who weighs coins to detect the tur value of the gold because people had a habit of shaving off bits of gold. This profession, as well as goldsmithing and banking was often held by families affiliated with the Jewish people.

Seems to me that this may well lead us to that well known banking family of Rothschild. Did they exist in 1789?