Sharpen AI v2.2.2 not doing anything on my Mac jpegs

Hello folks, I am testing the Sharpen AI stand alone before buying it, have thrown at it a wide variety of images - and I am getting no visible improvement results. I assume I am doing some wrong, help/insight is appreciated.!

I am not sure about this, but don’t JPGs already have some sharpening built into them in camera?
I shoot RAW these days, and use sharpen/stabilize on wildlife images, since I don’t have the world’s best long lens.
As an experiment, I converted a RAW file on which I had applied Sharpen AI to JPG (the original of course). Here’s the result. As you can see, it’s never going to be pinpoint sharp, but there is a definite improvement.