There's something great about being able to print something at home on A4, see how it looks, and know that it's going to be exactly the same (no stretching or cutting required) when you go to a print shop for an A1 or A0 print.
And yes there is a lot of legacy network effects around Letter size, which is why the switching costs are very high to make switching impractical.
Then we just need to standardize on A5 as a standard for bills mailed out, since it'll fit inside of everyone's filing cabinets already. A5 for taxes would also be nicer too.
Then get school supplies made in A5 size (easier for kids to carry), and finally after a silent transition period where there's less and less in the US Letter size, we can relegate PC Load Letter to the Office Space movie.
> almost a whole value
But not a whole value.
> But not a whole value.
Right, I said that because one of the dimensions is a half. However in practice those values behave as nice round numbers as well, because in the imperial measure context most things are sized to powers of two, i.e. 1/2, 1/4, 1/8 etc.
No idea what the advantage of a whole unit is supposed to be; nobody is sat around with a ruler measuring A4 cuts. The tolerances for paper manufacturing need to be specified in tiny fractions of a mm either way. As for actual typographers, they don’t use metric units, the size of the paper is not of great concern.
I added some more thoughts on the value of whole units in a sibling post. Like I mentioned it's mostly subjective, and has some utility to me when working with paper and measuring cuts. So yes indeed with a ruler, measuring cuts. :-)
1. You can easily calculate the weight of that letter without a scale, and stick exactly to the 20g limit (or whatever) for the cheapest postage rate. (I remember doing this in the 1990s for air mail letters to relatives.)
2. You can crush 2, 4 or even 8 normal A4 pages onto a single sheet while photocopying, and save paper/money. Although maybe by the time photocopiers were available in your country, the cost of paper was no longer an issue. (I would press the 2-on-1 or even 4-on-1 button when printing at university, to halve the cost at essentially no inconvenience.)
you can fold A(n) paper in half to make a brochure or booklet of size A(n+1), for example. it will fit perfectly into any envelope or folder sized to fit A(n+1) pages.
Not saying A4's not good. Just acknowledging that "nice round numbers" are convenient sometimes. Standards that use US-traditional measurements seem to do better at that for some reason.
Half a 20x30 sheet is 15x20, so the ratio has changed from 2:3 to 3:4.
1:sqrt(2) is used to maintain the ratio. The round number is at the start, with the area of A0 being 1m².
So what? The only thing I ever try to print multiple to a sheet is slides, and those are a different shape entirely.
(where "better" is actually "really annoying")