Fluorocarbon definitely has reduced visibility over wire leaders that is advantageous in any clear water situations. The visibility-factor seems to be most important for trolling applications. For trolling specifically, fluoro leaders are much easier on the body of the fish if they roll in the leader. Fluoro is comparatively weightless and doesn’t kink; however the bad news is sharp teeth can still cut it, so using a minimum of 80 lb. test is recommended and 100 or more is best. Wire leaders are better for many casting applications, as they are abrasion resistant and can’t be cut.