Your question is good, and I wonder the same thing myself.
I've been running 3 screw tactical Millet's for 3 years, with very good results. Lapping is a good thing on lower cost rings if both aren't cut from the same block. No loosening, no crushed scopes, no loss of zero or accuracy on any of mine. Having said that, I now have ATRS rings waiting for my ATACR, a NEAR from my S&B, and was considering a SPUHR for my S&B, but I don't think I NEEDED them. The SPUHR is just SO DAMN COOL THOUGH!!!! The NEAR is already tied to the S&B, so I left them as soulmates.
I've asked some people that I respect and trust about "why NF rings" or "why XX rings" are so much better. The answer I got went something like this: "Is your Mercedes better than a Honda?"..... some days I don't think my Mercedes is any better than a Honda. Better than a Kia, yes, but a Honda....hmmmmm. It's prettier, but it's likely not "better".
-J.