Outside of scientific and engineering fields, most everyday interactions people have with their units of measure do not involve translating between orders of magnitude, and yet the metric system optimizes for that to the exclusion of all other conveniences, through its focus on base 10 and "it's so easy, just move the decimal point!"
Meanwhile, in most other areas of life, dividing into halves, thirds or quarters is overwhelmingly more common than dividing into tenths, hundredths or other powers of ten. If you wonder why the "unintuitive" imperial units have such staying power, consider that 12 and 16 are more typical bases for them, and 12 is essentially ideal (evenly divisible by 2, 3, 4 and 6) while 16 is better than 10 (evenly divisible by 2, 4 and 8).
Kitchen cupboards, appliances etc are designed in multiples of 300mm, which has factors of 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 25, 30, 50, 60, 75, 100, 150, 300. The smallest part is still in mm, not awkward fractions of an inch, and the whole wall can be put in mm: 3880mm. That's easy to understand, but 152 inches is less so (who uses inches for something that long?). 12ft 9in is presumably intuitive for those familiar with imperial, but annoying to convert as soon as it needs dividing or multiplying.
Also, imperial units didn't have much staying power in the ex-British Empire, apart from in Britain.
I think the main question is why we feel a need to impose a single one-size-fits-all universal unit set onto disparate domains with different ideas of what properties make a unit desirable. There are domains where base-10 units are a good fit, and other domains where base-12 units are a good fit, and I don't see why we need to try to force one set of units to serve both.
If the nurse had been used to working in kilograms, she would have realised 25kg was a huge sack of coal / much bigger child / whatever. (She would have known that her own weight as a child was 40kg or whatever.) Or, if the country had been properly metric, the scale wouldn't have had the option of pounds.
(Hopefully, you see no reason to divide a child into 3, 4 or 6 equally massed parts.)
So... the metric system magically prevents data-entry errors? Or somehow you can't believe that there actually are common everyday tasks involving splitting something into halves, thirds, quarters, etc. and so feel a need to engage with a hyperbolic child-dissecting strawman instead?
You're really not doing a great job of presenting your case here.
Order of magnitude is defined as power of 10 precisely because we work with base 10 system. The same would stand for base 12, only the order of magnitude would be defined as a power of 12.
Yes, to me, as a SI person, argument for 12-based system looks ridiculous :) . Starting with "we don't have 12 digits" and then just saying there's no problem with division by 3 - you sure can handle the .3333... infinite tail in your head; by 4 - those .25 with properly adjusted comma - by 5, 6, 8, 9... It's all just a matter of habit.
Meanwhile, in most other areas of life, dividing into halves, thirds or quarters is overwhelmingly more common than dividing into tenths, hundredths or other powers of ten. If you wonder why the "unintuitive" imperial units have such staying power, consider that 12 and 16 are more typical bases for them, and 12 is essentially ideal (evenly divisible by 2, 3, 4 and 6) while 16 is better than 10 (evenly divisible by 2, 4 and 8).