Even though these pliers really only do one thing—bend loops—they are invaluable for getting a professional look. Round-nose pliers have smooth cylindrical jaws that taper to a point and less likely to bend or become misaligned. You can make a variety of loop sizes with this tool by simply moving the place on the jaws where you're bending the wire.
With conical jaws, they can make perfect loops and rings. If you need a tiny loop, the very tip of almost any round-nose pliers will do.