IMO one nice (un?)intended consequence of the liquids restriction is limiting liquid spills on the floor of the plane i.e. somebody can't spill a 2-liter bottle of Mountain Dew or IDK, a gallon of laundry detergent on the plane (Sure there's the beverages on the plane or whatever you can buy post-security but they're usually not that large either) -- there's enough mess without having to deal with people porting around whatever amount of liquid they please.