When everyone has 1 name, and their father has 1 name, it makes the Gabbai’s job so much simpler, as well as reducing Tircho dTzibur when calling up people.
I signed several Gittin under the tutelage of a certain Choshuv Rov who was frequently Mesader Gittin, who would only accept Eidim who had 1 name and whose father had 1 name, to cut out potential Sha’alos. … He would have loved to do the same for picking divorcing men & women, but obviously realized he had to deal with the issue of multiple names of divorcees, but wasn’t interested in causing extra issues when it came to the Eidim.