You kind of prove my point here: people typically fail to guess weights of a few grams.

Edit: corrected density, I had previously used the actual density, not the density of loose sugar, which is less.

But yeah, no, chocolate bars are usually 50-60g. Which is also a thing, because they used to be 72g. I remember that number specifically because that's two of your "ounces", except on a second Tuesday during the ides of march when an ounce is like 85 grams. But only for red things. There's a whole separate system for blue things.

I just looked one up, it's less than 20€, 0,02mm of precision. There are just 4 markings between 1mm and the next.

So instead of 9 markings, each marking adding 0,01mm, you just add 0,02mm. Doesn't sound complicated at all.

I haven't found an analog one, but a digital one with 0,01mm of precision costs 30€. Maybe an analog one costs 50€.

So if adding 0,02 is too complicated, you can just buy a 0,01 one for 30€ more. Which is the price of a pizza for a tool that will last years.

Anything more precise than 0,01. You probably have a lot of experience using a caliper. Whatever method it uses to display that precision is gonna be second nature.

Another quick example, my foot size is approximately a foot in length and I paced off a room at 10ft x 20ft so the area is about 200 sq ft. The equivalent would be that my foot is approximately 0.3 m so 10 steps x 0.3 m x 20 steps x 0.3 m = 18 sq m.

Imperial units work well when you want to use relatively small whole numbers and high accuracy isn't super necessary, but ultimately it just comes down to preference.