Do you not remember the videos they made showing the faster load times before, when they were preparing to launch their major OS update? Two side by side consoles, loading into NSMB U? They absolutely are showing the exact load time of this, that's the point of the demonstration.
I think you're failing to understand something. The point of the feature is to start a game as soon as the OS loads. This means you don't have to wait for the OS to load normally, pick your user, then select the game from the OS once it has loaded up. This makes it faster, not "look like" it's faster. The load times may be the same, but since you're navigating less it cuts down on time by more than you think.