Absolutely, but you're reducing the risk of communicating with people who may be using the roman suffix without writing in Roman numerals. In that situation, you'd see 2M rather than MM.
The British billion went out in 1974/5 (Wilson/Healy). One billion is 1,000,000,000 and you shouldn't expect ambiguity there.
In practical terms, it doesn't matter. It'd be extremely unusual to be at the scale of the old billion (1,000,000,000,000)
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This is similar to a justification of using `i` as the variable for an iterator, or `x` and `xs` for head & tail. There are logical reasons, but it's mostly convention.
Well you're gonna be really disappointed to find out lots of people do use "mm" particularly in finance, and that Roman numerals have been used far longer than the SI system has existed.
Just because you don't use them, or aren't aware they are used, does not make it unnecessary.
By unnecessary I meant the second M in MM is redundant (since M = Mega = 1e6 is enough). And yes I am disappointed, probably just as much as people's use of imperial units :)
Edit:...
>Roman numerals have been used far longer than the SI system has existed
Indeed it has. But has its use as a suffix existed for just as long? BTW I am also disappointed that the people still use Roman numerals :) (also completely unnecessary, the Indo-Arabic number system is "better").
> An expense of $60,000 could be written as $60M. Internet advertisers are familiar with CPM which is the cost per thousand impressions.
> The letter k is also used represent one thousand. For example, an annual salary of $60,000 might appear as $60k instead of $60M. [0]
k and MM are unambiguous. You don't want to stop & think, and you definitely don't want to be off by a factor of 1000. So it makes sense to avoid typing 'M' if you have any risk of being misinterpreted.
It's mostly about the reduction of risk, it's VERY rare to see M used in this way.
This is infeasible, and what does it mean to reject something in a written document?
I don't understand what you're trying to accomplish here: you're arguing against an established convention in a sector of the market which you don't have experience with.
The upside if you're successful is that I don't need to type an additional 'M'.
The downside is that it requires enforcing a blanket standard on an industry, rather than letting it converge over time to an unambiguous standard.
Help the convergence along by objecting to the use of M=1000 wherever you see it. We already have an unambiguous standard (it is the SI system of units and suffixes if you are unsure). People should be using it.
M is ambiguous between the Roman (M = 1,000), the SI prefix (M = 1,000,000), and metres (screen readers).
$1MM (capitalized) or $1mn (more recent) reduces the ambiguity.
https://en.wikipedia.org/wiki/MM#Units_of_measurement