I own a couple of helmets as does my son and GF. Each of the helmets padding is different, by either thickness or density. I would assume that it doesn't matter if you pull the padding out and wear a beanie under instead. The padding doesn't look like it provides any added protection and is just a measure of comfort.
But, I'm no expert.
Most of my helmets don't really have padding but more of a harness to hold your head into a specific location.