What I'm saying is that when you're following a target with the mouse, you simply move it without thinking about how to compensate — you just follow the 'circle' with the mouse. There's no real skill involved, yet you gain the advantage of faster turns.Not true.
If you push the mouse up in FAoff with rel. mouse on, you start to pitch up. This rotation won't stop just because you've stopped pushing the mouse upwards. You'll keep pitching up. If you want to cancel this movement, you need to pull the mouse back down, i.e. you need to counter the previous input.
It's very different with a joystick: every movement needs to be actively compensated. It's simply undeniable, and every PVPer chooses the mouse for this exact reason.
Yes, there are a few exceptions — some HOTAS or HOSAS pvpers— but they're few, and they all have to rely on third-party tools for curves and fine-tuning.