Because it looks better.
Unless you want a massive egg on your head when you run a beanie under you padding to keep your jack flappers warm then fuck the padding off. Padding isn't needed when you have a beanie in there , the beanie does what the padding does but better. The shell is the only thing protecting your head for splitting open like a watermelon.
Goggle's on the outside looks stupid , Cluttered and only someone as cool as shaun white can wear them out there. It looks much better to have them on the inside.
Earflaps look chat , so does earflap headphones , bluetooth thingo's , smith helmets , pro-tec helmets and burton helmets. They all bite the big one