You could put a sharpie mark where you want to aerialize (sp)
your backcast on a full cast (many try to put way too much line in the air on the backcast ruining the cast) Other than that, it is to identify your line. At least all I can think of. And roll cast? The more line you put behind you, put behind the rod, the farther you can roll cast. That is one reason anglers learn several of the spey casts. Spey casting is glorified roll casting, and it places a big "D" shape of line behind the rod adding line weight that loads the rod better than a standard one handed rod roll cast. Double hauling the roll also adds line speed that increases distance.
I dunno, 40-50ft if you work at it I guess. I use the roll quite often because I wet fly swing soft hackle flies a lot.