Going from a simple old $10 stick to a good $70 stick-and-throttle setup with 20 buttons doesn't do much either, does it?
It refines your control. It lets you do more with the skills you have. It makes flying more efficient in that you can do what you want with less effort. The end result might not be much different, but the path to that end result might be a fraction of what it used to be.
I'm guessing the same is true of rudder pedals. They (in my mind) will help a HECK of a lot with basic flight, with getting me from Point A to Point B with the least amount of problems, and will probably enhance my gunnery a tun (I use rudder for fine tuning shots a lot). So it won't make me better, but it will make me more efficient, able to do things better. THEN, once I can do things easier, better, faster, maybe I as a pilot will become better skilled (moving on to newer levels).
^-- That's why I want pedals. That's my reasoning. I've never had any to date (too much $$$).