Two useful things I've found with fly lines is first, fly lines with longer heads are very useful for mending at longer distances. In addition, the longer head allows me to aerialize more line making longer casts much easier.
The D River comes to mind. With two rods rigged, the rod with the long head line was able to reach out to the fish plus I was able to mend to catch fish where the standard line could not.
Second, textured line causes less friction on the guides and rod thus shoots further. Textured shooting line helps with distance, but many anglers fail to utilize shooting line in short distance situations with obstructions not allowing a longer backcast. In other words you can cast a shorter line in the air and shoot to your target.
Again, on the D River, the textured line was superior for distance and even more accurate shooting line short.
Anyway HTH.