Meme of two women fighting while a man smokes from a pipe in the background.
The women fighting are labeled "mathematicians defining pi" and "engineers just using 3 because it's within tolerance"
The man smoking is labeled "astrophysicists" and the pipe is labeled "pi = 1"
That's close enough for radio. You can't cut an antenna much closer than that precision, and it'll stretch or shrink with temperature anyway. I guess the error could add up enough to be a problem in lengths of fibre optic cables, especially as they run at about c/3