I used to think there was too much wasted time in casting a fly, which would impair my catch rate when compared with spinning gear. I still incorporate spinning gear for certain fishing situations, but for the past 2 years over 50% of my fishing trips are with fly-fishing gear only. My catch rates have gone up considerably!

Like you, much of my fly-fishing is done on public ponds for bass, bluegills, crappies, and the occasional catfish. I usually target bluegills, and the bass are "bycatch". When I target bass specifically, its with topwater flies. If there's bigger bass in deeper water, they have (so far) been fairly safe from me. I might go after them more next year with some deeper presentations.

For bluegills, smaller bass, and crappies, a slow presentation and/or a slow descent of the (non-topwater) fly, or tossing lightweight topwaters are extremely productive methods, and this is much more easily accomplished with fly gear, in my opinion.

Somewhat of a similar approach might be possible with spinning gear and a bobber, but its much much more fun to have the more direct connection between me, the fly, and the fish. (A bobber puts a bigger angle in your line between you and the lure.)

Just my opinion, of course, but my observations are right in line with yours!