My question deals with leaders. Each leader usually consists of 3 or 4 different lines of various strengths connected by different knots. Until recently, most knotless leaders available for purchase were freshwater leaders with stronger tippets. The butt section diameters were too small to transfer the energy from the unrolling flyline, and hinged badly. Even though knotless leader designs have improved, I still feel that customizing a leader for given conditions and fly styles is much better.
Conditions can change quickly on saltwater.
The wind can pick up or lay down, or a change in tactics may require a larger, heavier, or lighter fly. Knots are weed magnets, so if you are fishing in an area with floating grass, such as shallow water redfish or dolphin on weedlines, you'll have better luck getting a fly through clean with no leader knot connections. I've had best results by sticking to monofilament from the same manufacturer through all the connections. From what I read the best fisherman see more fish in the water. William, successfully spotting fish takes practice.