Yes, it’s from a book called “Uncle John’s Bathroom Reader” and that book was resting on a closed toilet seat in a nation that only kind of uses the metric system in certain situations… however, you’d be surprised how much you can learn after a single visit to any local fast-food joint!
You clearly haven’t been a kid measuring a 7m penalty kick on some random field. It works perfectly fine.
I would rather walk-measure the side of a field than tiptoe-measure it.
If you want to be more precise, you need to know your body’s measures. Like the span of my hand from thumb to middle finger is 21cm. 20 if I’m not that concerned about accuracy. I can measure quite a lot with that. Or 170cm for my arms spread apart (wingspan).
You’re right, I have no interest in sports. Though in that case under this modified metric a decametre would be approximately on the same scale as the previous metre.
Don’t get me wrong, imperial sucks, but the scale of the typical measurements with typical units lands nicely in what the human brain is good at visualising - small groups of up to about 10 (see my comments to other people in this thread). I think most people would prefer when the common measurements they make with common units end up in the range of 0.2 to 10-ish. Centimetres are too small for that and you measure using dozens or hundreds of them, which starts to lose semantic meaning, which makes visual estimation a bit trickier, especially with comparative distances. You start thinking in terms of tens or hundreds of cm visually to keep it under control which is just another layer of cognitive load. I think the perfect unit system would avoid this as much as practical. The existing metric metre is fine for outdoor activities, but I would argue most people aren’t out measuring fields all day, they’re looking at things on the same scale as their own body for the most part. Metres are a bit big for that.