First use of the star
The eight-pointed red and black star was adopted by the AFSC on Nov. 13, 1917, as its symbol. The star was first worn by British Quakers during the Franco-Prussian War in 1870. Quaker relief workers at the time wanted an identification to differentiate themselves and their supplies from other groups who were carrying out similar efforts. The star was in use by the London Daily News Fund on its shipments "for the relief of the French peasantry." Until the star was adopted, the Quaker workers had used the British Union Jack as well as the Red Cross flag. This combination caused some confusion among the Prussian soldiers and made it easy for French civilians to mistake the Quakers for Red Cross workers. Neither group desired this confusion of identity.
The decision to use the star symbol of the Daily News was made with the newspaper's approval. This enabled Quaker relief supplies to be given the same reduction of duty fees and ease of passage by customs authorities as those shipments made by the Daily News.
Origin of the star symbol
It is not known who originally designed the star, although several stories have been told to explain the source. The most common story--with no apparent basis in fact--is that Quakers helped the French city of Nancy during the Franco-Prussian War, and authorities there asked the Quakers to use the symbol of their city as a token of appreciation for the help they had received.
The star is not unique to the American Friends Service Committee; it is used by other Quaker groups as their symbol. There are variations in the design of the star, but most spring from shared Quaker roots and represent a common commitment to service and the spirit in which it is provided.
—Written by Jack Sutters, former AFSC archivist
Source (found at): https://www.afsc.org/story/red-and-black-star
Knowing that helps tremendously with family research, because all of the Quakers keep their own "official" records in the Monthly Meetings that are in addition to any town/county Vital Records. Many times and places in early US there were no town/county Vital Records, and in many instances, things would be recorded in the Meeting Minutes that weren't in the VR.
Also, Quakers were required to get permission to move, so records of when and where family groups go are also recorded. Eventually, people slipped away from the faith and that is why some branches are longer in the minutes than others.
If I happen to come across indications that a person was particularly active in their Quaker community, then I set the pic as a marker if the profile has no other image. It acts as a signpost for other researches. Sometimes knowing that someone was quaker helps to evaluate potential spouses.. as you would have to get approval to marry, and you were forbidden to marry someone who wasn't quaker or joined. Otherwise you got excommunicated (which also shows in the record). It particularly helps in the late 1700s to early 1800s when people started expanding west and there were enough people that there are many more people in a town with the same name about the same age. Also, New England Puritans became sloppy (or I should say not as strict) about keeping Vital Records during that time, and many new communities on the frontier went for years without "official records" or even official recognition.
So if you know someone was quaker, it really helps narrow down where to look and has much higher probability of finding something useful.
Same with Swiss/German Mennonites and Anabaptists in Penn and NJ and Catholics in general if they used parishes.