What is the point of Quick Navi on the A99?

Can somebody explain to me the point of the Quick Navi screen on the A99? I gather that it was used on some older Sony DSLR models, not sure which ones (A700? A900?).

I simply don't see any advantage here over the way the Fn button works on the A77 or the way the Fn button works on the A99 if you don't use Quick Navi. What am I missing?

Will