I just like to tinker - I was looking at the service manual, and it describes how to get in and shows the screens you should be able to see, so I just wanted to try it out, so I guess it's to amuse the nerd inside me
I don't think there is anything useful to actually set in there. (interestingly, in the service manual they show a screen which mentions a "camera system" (and the screen is completely different than the one they show for the NAV system) - there's also one for "speaker test" which I was curious about)