I have it on my PSR-E433. Not sure if it's on the newer E473 or not. But honestly, it's not a feature I use. It's funny this subject comes up because I'm working on recording a multi-track song, and I just happened to notice the note/staff display changing the displayed notes as I was playing the other night.
But like I said, while it's a cool feature, I never use it. It might be beneficial for someone just learning how to play, to see how the keys relate to the notes, but even then, the player would likely be concentrating on the actual physical keys, and whatever music he or she is playing. It's best to just learn the notes of the keyboard directly. C is the white key right before the set of two black keys, and F is the white key right before the set of 3 black keys, and just go from there.