M is not the international standard abbreviation for 10^6. M is the SI system for 10^6, which is not the same thing - SI has some extra rules.
If you write MM you are clearly not using SI (since it makes no sense in SI), so it's not that hard to figure out.
M has meant 1000 for a lot longer than it's meant 10^6.
And BTW, lowercase m means milli, so by your logic mm should mean 1/1000000 - so tell me again why MM is worse?
M is not the international standard abbreviation for 10^6. M is the SI system for 10^6, which is not the same thing - SI has some extra rules.
If you write MM you are clearly not using SI (since it makes no sense in SI), so it's not that hard to figure out.
M has meant 1000 for a lot longer than it's meant 10^6.
And BTW, lowercase m means milli, so by your logic mm should mean 1/1000000 - so tell me again why MM is worse?