As a rule of thumb, any head lumps, combs and crests on helmets were here to protect the top of your head, and to a lesser extant make you seem taller/fearsome/sexy. A top-down strike on your head can really mess you up regardless of how strong your helmet is, because the energy of the blow can still either cave it in or ruin your neck, that kind of niceties. Having a raised piece there will tend to deflect blows to the side and generally stop your opponent from getting a nice angle to work with. It’s a pretty essential design component found in helmets from the ancient world, as seen above, right up to WW1 where saber blows were still a hazard. I think the French Adrian helmet was the last one to be made with a comb like that, where it doubled as a way to cover ventilation holes. :3
Of course it’s very diminutive compared to old dick-hat over there :y
