As I stated earlier, I've used both. I learned mil before I learned moa.
I truely believe moa or IPHY is a better system, especially when talking about small amounts. We judge a miss or a wind drift or even some holdovers in inches naturally (at least most of us do). It just comes natural to refer to things in inches and therefore converting to shooters minute is easier................Even target size is referred to in inches (example: the X ring is 10" wide, that deer is 20" from back to belly, wind's gonna push us 5" left, gotta hold about 3" high at 300, ect,ect.) Who calls a miss by 1/3 mil unless they are trained to and have a mil reticle??? Besides, 1/3 mil is a pretty substantial miss IMO........it's nearly 10" at 800 yds.
Now if we're trained to think in cm and meters and mils and measure target size in yards.........that's another story.........Or, if the spotter also has a mil reticle they're looking through, then it doesn't make any difference. He calls a 1/2 mil miss to the left and the shooter then dials or holds a 1/2 mil right. Same scenario when they both have moa reticles.
Problem comes when they have different reticles or the spotter has no reticle.
Problems also come when the scope adjustments don't have the same units as the reticle. Imagine your spotter calling out a 1/3 mil correction and you the shooter having 1/4 min clicks (which I believe was kinda the original point of this post)........I can't convert 1/3 mil to 1.15 moa in my head in a couple seconds during the heat of the moment........how many can?? Same goes for calling a miss in minutes and the shooter having 1/10 mil clicks...............they need to be the same for lack of confusion and efficiency/speed.
1mil=3.44 moa, 1moa= .29mils..................these aren't easy numbers to juggle around in a hurry in my head. But, a 10" miss at 800 yds easily and quickly converts to 1 1/4 minute in my head. (not exactly, but very very close)
Sorry to be so long winded. It's obvious to me, but I seem to have trouble making it obvious to others. Hopefully that kinda answers your original question.?
I agree with your points and that was pretty much what I was thinking and why I posted. I don't have issues with using MIL but in the original examples I gave, when there is a miss the miss will be seen in inches for most guys in the US. Converting inches to MOA correction in those examples are faster and less likely to have errors IMO than seeing the miss in inches then doing the math to factor to mils. Again, I get that either way can be done with practice, and I use both methods, just trying to figure out which is going to be easier for newer shooters that don't have matching reticles to the spotter or don't have a ranging reticle in their scope at all. I think in most cases MOA will be easier and have less chance of error.