If you tie serious streamers like pike flies, GT flies or Barracuda streamers then you need the real stuff to catch those big monsters: Hedron Saltwater Flashabou Extra Wide! This material is highly appreciated all over due to colors and movement. Nothing is better like the original made by Hedron in USA
Recentrly lots of European guys use this material to make backs for river nymphs. So as you see, saltwater materials can be used with great success for making grayling and trout flies too :)