The smallest particles are not actually balls, but are wibbly wobbly. To measure something we need to interact with it, even if we interact with it using light. But because those particles are all wibbly wobbly, we can’t say for sure where they are exactly. And that unsure distance is Plancks length.

Disclaimer; I am not theoretical not a physicist, now eat your vegetables.

When I asked the boss, who has been in the business for a couple generations, why it says here 4000 instead of 4m, he said what I am telling you. So you don’t mix up measurements.

Sure. I’m not a professional machinist. I have worked on roofs and all sheet metal things are in mm. I have even worked for a company that makes those metal things and as a customer for another one. I also was by far the best at technical drawing in school, not to brag. And all the schematics for things I have seen are in mm, for example https://www.iclarified.com/images/news/48931/228250/228250-1280.png . Disclaimer, all the schematics that are not in, ugh, inches (or architecture).

Sure, if I made something for someone they can give me dimensions in Smoots for all I care. But I would transform it into mm, and would never buy tools that don’t use mm.

For context, I am not in an english speaking country nor Myanmar.

Edit: Actually I have seen house schematics in mm as well. I thing they now give out in m, but use mm internally (depending on architecture firm).

Every professional that deals with stuff that needs around 1mm precision uses mm. Metal roofing, gutters, any machining, etc. It is to prevent ambiguity. I used to build roofs and for like wooden beams we used meters and cm, but that was because a couple mm here and there rarely ever mattered. All in all using mm is usually the best choice.

That is not what genocide means.

I like the old amd ones.

That and stop legal bribery. Disclaimer: am not usaian.