Science

I imagine it's been developed and lost periodically, and some people are averse to irrational numbers. Greece just had continual credit in our intellectual pedigree (as opposed to, say, the Babylonians who had more advanced trig than the Greeks before them and the Greeks were aware of them in some ways).

I think you also need a lot of rectangles and squares to find it necessary. I imagine buildings, but even today a lot of materials are cut to fit (also, the building I am in is not rectangular along any dimension). Maybe legal rectangular plots of land? Idk