I realized I have an old skateboarding type helmet laying around, and tried it on for kicks today. It seemed to have a much snugger fit on my head, and would move around less while riding. It also seems beefier, like it could offer better protection, and seemed to cover more of my head in the back.

Question is, it seems to me that this could protect me better, so why don't you see more people riding with these types of helmets? Is it because of the ventilation, weight, style?
What do you think some advantages and disadvantages are between a regular bike style helmet, and an aggressive skating type helmet?