For the Smokies I use a neutral or dark colored fly line, Double Tapered. I'll bet that 90% of the time I don't have more than 8-10 feet of fly line outside the tip top of my rod. Mind you, I am not talking about tailwaters, or large pools on the lower end of Little River. I can't see paying 100 bucks for something that I only use a small portion of. That's what I like about a double tapered fly line; I can reverse it when one end gets cracked and dirty. Fly lines in the Smokies last me for years...
If a person is fishing waters that take long casts, then I can possibly see the benefits. I wonder if the "indentations" on the line collect grime and dirt?
Many go fishing all of their lives without knowing that it is not fish they are after.
- Henry David Thoreau