There's no telling whether or not this video actually tells us anything about the Galaxy S6. The fact that the phone in Samsung's Knox tutorial looks a bit like a recent leak is probably just a coincidence. But since its an official Samsung video it at least provides some insight as to what Samsung might be thinking about in terms of smartphone design.
Samsung is rumored to be "starting from scratch" when designing the Galaxy S6, so there's a chance it'll look significantly different than the Galaxy S5. Check out the video below.