If you deer hunt in very heavily pressured area's, scent control AND hunting proper winds is critical.
If one uses stinky shaving cream, stinky soap, then applies stinky deodorant, puts on clothing his wife washed in "spring clean" laundry soap and then pumps gas in his hunting clothing and boots, he's more apt to be the guy that has all the "ones that got away" stories.
Successful deer hunting isn't about doing things right, per se. Being a successful deer hunter is more about eliminating all the little things that can and do go wrong, one by one. And scent control and entry/exit are two of the big "little things". Don't forget, your scent can linger long after you've left the area, thus still spooking deer hours after you've walked out, if your exit is done improperly.