What the heck is fly fishing? Glad you asked!
Fly fishing is different. The lures in fly fishing weigh very little, meaning that you can’t easily cast them into the water with a standard line. The weight of a traditional hair jig in spin fishing will cast like a bomb. You can throw it out, and it’ll travel through the air with no issue whatsoever. A fly used in fly fishing, by contrast, doesn’t have the same weight - at least not by itself. Thus, in fly fishing, the line itself is weighted.