I almost always use US as a pre-build for Hoover leaving the palace available for ToE. If I get my timing right I complete Scientific Method, switch from the palace to ToE which completes the same turn, choose Atomic Theory and Electronics as my free techs then Hoover completes one turn later.
Getting back to the original question, according to the war weariness article in the war academy, Universal Suffrage makes one unhappy citizen content, presumably in each town. This is not worth building for the happiness effects, but it gives you something to build during the industrial age if you are playing 20k.
Oh, I see that all my previous zeal to get US at any cost was in vain.Rather useseless thing for its price indeed.