I'm actually a reformed Catfish guy (started chasing Striped Bass and White Bass)

I have A LOT of circle hooks in my inventory. The fly pictured was a one-off that I did, with the intention of proving/disproving a theory. Circle hooks work by catching in the corner of the fish's mouth as they swim away with the bait, and the line comes tight and the pole loads up. I tied up a bunch of Belly-Scratcher Minnows on Gama B10S hooks. I've caught a couple fish on them, but have actually watched as a fish takes the fly, and miss the hookset. I am hoping that using a Circle hook means more hookups and less missed strikes. Of course, I have yet to actually fish that fly.
PunyTrout, you may be completely correct as well. I also fish a lot of inline spinnerbaits (I assemble my own), as well as jigs on jig-spinner frames. None of those use circle hooks, but I hardly ever miss a strike, as the line it already tight with the fish hits, and it's an almost instant hookset.
Why use a circle hook? They are designed for using bait that gets swallowed. Then, slowly reeled until the point sets into the corner of the jaw. Think catfish.