Almost all DAWs I've used allow you to use the mouse wheel while clicking to increase/decrease the value on a knob.

I only use logic now but used FLStudio in the past. I’m by no means an expert or anything, just an audiophile ex-musician turned software guy and find that it’s similar between flight simulator and logic. With FLStudio I did everything with midi controllers so I never used the mouse that way.

I don't really see how that would be precise enough, the mouse wheel has a DPI of like 10 vs 400-800 for a mouse. A mouse wheel has like 25 notches in a full rotation and even MIDI CC values go from 0-127, that's 5 full rotations, that doesn't sound practical as it would be far too slow. And many parameters require much more precise control than 127 steps.

I don't play flight sims but I imagine most flight surfaces require small adjustments and the effect of those adjustments on the aircraft is naturally smoothed out by the dynamics of the plane (you're adjusting an acceleration).

I imagine the scroll wheel is not suitable for dogfighting.

I would assume the better programs implement some velocity control, turning it quickly will cause it to increment in larger steps, turning it slowly will increment single steps. This is how I have done it in the past when I have used the scroll ring on my trackball in PureData.

I would also assume there are detent free mousewheels with a far greater number of steps, there used to be. The scroll ring on my trackball is detent free and quite fine but it is also ~2" in diameter, considerably larger than the wheel on any mouse.