Well the real amps convo is just a side quest.
The real question is, why have a prePost-Z control in Stadium at all? All I can think is, one of the DSP engineers said "we don't want to pull a Fractal and unlock all of the controls in the UI, but maybe we can invent an original control that gives people some of the customisation they are used to on other platforms" and there you have it.
You can be sure as shit that under the hood, their amp models have all the same kinds of controls that Fractal does; hell, even Fractal probably have a lot more that they're not showing too.
Likewise with the hype control. Someone went "hey, we noticed this other platform consistently gives their amps more gain than the real thing, and a smiley EQ curve.... let's make a knob for that" ....
It is where the distinction between accuracy and product design becomes a thing.