Not talking about screen sizes obviously, but I really don't have an intuition for what 'less than half an inch' thickness is and I'm sure there are a _lot_ of people who use English as their interface language outside of the US.
Go to other local websites and the specs will be in the local units (most likely metric), but even in Europe, display sizes or car wheels are almost always denominated in inches.
This is totally fine for companies targeting US domestic markets I guess but I suspect Apple sees itself as an international company and they should have the budget for proper internationalization.
Maybe they just don't care for people to know how thin the Air is, but the number of search results for 'thin' on the page let's me think otherwise.
It's the total spending dollars that's important. By using US customary units, you get 25% of the world GDP in one easy-to-do-business-with entity.
... so? Total spending is the key factor; Apple gets exposure to 25% of the total human economy by catering to one polity which is also the easiest one to do business in. That's a no-brainer if I've ever heard one.
By contrast, India's economy is only 3% of the world total. [0]
It's interesting to note that this understates US dominance in luxury products - due to being rich-person-friendly, they actually have far more than 25% of the world's rich people - 38% according to page 28 of [1]
Which market would you rather target?
[0] https://data.worldbank.org/indicator/NY.GDP.MKTP.CD?most_rec...
[1] https://www.ubs.com/global/en/family-office-uhnw/reports/glo...
'less than an inch (11.5mm)' would still be a better specification if you want to have a version where you rather err towards US customers.
I'm not offended by seeing inches, just irritated that you wouldn't cater to the rest of the world.
If you check these specs in a month, it'll probably tell you the size in mm. I just checked the iPhone page from here in Canada and it says this: 5.77 inches (146.6 mm)