I'm a 6'1" man with size 3 feet which means every time they measure my feet at a shoe store, the Brannock device tells me I'm not a man
I was born with feet in the 1st percentile of the population and they stayed that way even despite getting taller. Now every shoe shopping experience is awkward af.
I don't think anybody is asking to measure his feet, but these measurement devices are practically everywhere that shoes are sold, so it's easy to check for yourself.
I never buy clothes online, exactly because I always try them on to check the fit before buying them. I haven't measured my feet since I was around 15. I know my foot size, so I know that shoes in the range 42-43 are a good fit, depending on the shoe model. I don't need to measure my feet when I buy shoes to confirm that they're still around size 42.5.
I mean, your feet typically don't really change size after you grow up? I just buy whatever size I last bought.
Edit: tho to be fair it's not even always the same size because the size that's comfortable highly depends from shoe to shoe, I always have to try on a few pairs to be sure.