They can reverse the effects of ageing eyes when used "correctly"
My favorite shooting is the NRA small bore 50 foot target shot at 50 YARDS!
I don't see well close up, But I can see the front sight aperture ring encircle the target black quite well.
Though this shooting is strictly for my own pleasure, my "scores" are not too bad at all. I have no problem keeping five shots "in the black" for most (not all) the targets on a page.
Note, those target rings are 1.5 inches diameter. Without the "peep" sight , I can not see those targets at 50 yards. With the aperture, They are in good focus through the front aperture. I've used a blade front insert as well, and the shooting is about the same. There is more light available with the post over the ring front inserts. I will try the glass insert with an "air hole" aperture some time soon. I just have not got around to making one, and the sight I have is not supported by those who produce the glass front sight.