Comment by dsign

I've been working with paper sizes a lot for the last year, and I've rarely thought about the square root of two ratio and when I've, it has been just to amuse myself. However, knowing that to get an A5 piece of paper I just need to cut/fold in half an A4, and that I can get to A3 and A2 by adding A4s, has been really useful. If I were in USA, didn't have that, and instead would have to install yet another new size system in my head[^1], I would despair.

[^1]: This is fun! https://papersizes.io/us/