On the T7/744 you need to have the freq and LOC course hard tuned on the NAV RAD page.
Is it simply a system that gives better peripheral and faster/quicker recognition needed because of the higher cockpits of the wide bodies resulting in greater slant ranges for seeing the runway lighting,
I guess the logic is something like that. the display sits just at the bottom of your peripheral vision and as Pontius says it's very intuitive to use
All that said our latest T7s are being delivered without them, story goes they (well the one's we use) are expensive to maintain and in reality are rarely used in anger.