This thread is mostly about red dot sights for pistols. The sight above won't work on a pistol, since the web page states it has a 3.7" eye relief. You are correct in thinking that a prism scope with an etched reticle will give a much better visual picture with some types of astigmatism. But the tradeoff is that all prism optics have a set amount of eye relief, even if they have no magnification. Traditional red dot sights with no magnification have "unlimited" eye relief, and they really do work fine on a traditional rifle mount, or a scout mount, or at arms length on a pistol.
I have not used the sight above, but I have used other prism scopes on rifles, and they work quite well. For people with certain vision problems, they are probably the best choice. However, I am not aware of any prism optics with the extended eye relief that would be necessary on a handgun.