A sediment bowl is an entirely different thing than the fuel pump bowl. Like your friends said, they usually mount so debris and water stay in the bottom, and fuel is drawn off the top. Your pump originally in WWII had a metal bowl, and someone decided that seeing inside the fuel supply was a good idea, so the glass bowl replaced the original design. It is more useful to see if you are getting fuel flow than as a filtration device. Now there were Carter and AC and other brand fuel filters that mounted to the carb that were more of a sediment bowl design.