The source in question is very useful to a historian as it provides an insight into the kinds of arguments being advanced by the women's suffrage movement in Edwardian England.
The source is a cartoon, depicting in pictorial form the double standard pertaining to the vote. The five pictures in the top half of the cartoon show us that women can be mayors, nurses, mothers, doctors, teachers, and factory hands, yet are denied the vote. Whereas the five pictures in the bottom half show us that men can be convicts, lunatics, proprietors of white slaves, or pimps, unfit for service, and drunkards, and yet can still exercise the right to vote.
The cartoon, which forms the basis of a poster put out by the Women's Movement, tells the historian not just what kind of arguments the campaign for female suffrage put forward, but how they put them forward.