If you make that build as a small forward then you get standing contact dunks pretty early on and driving contact dunks at 91 overall. They can be effective dunkers on offense if you have a weakling trying to guard you.
They do, but slashing defender is the better overall build if you're going to make a mixed defender since you'll be more athletic, have better scoring ability, and will eventually get the driving contact dunks. The 5 point difference in rebounding isn't very noticeable since both builds get silver hustle rebounder. And you don't need breakstarter if you and your leakers know how to stay within the safe range on outlet passes.