I am not using them.
After trying many different setups over the years, I have found that it is much more efficient to have a rifle that is set up for a particular use. It is better for me to have a gun for long range and a gun for short range.
If you are wanting a single gun to do everything, learn how to do everything with it.
If using various sights and scopes and zero's at different distances helps you shoot better, fine.
But for me, I like to keep things KISS. Especially if under pressure, and especially more-so if I was under fire or threat.