Comment by zdragnar
Bingo. Take the swapping of periods and commas between US and maybe Germany.
If you see a price in Euros and there's a chance the browser converts the number to my locale, then the price becomes completely ambiguous. Information is lost unless I change my locale just to see if the number changed.
If, on the other hand, the browser doesn't apply such formatting, then the number is probably the number.
What's more, wouldn't you need to specify an origin locale so the browser knows how to correctly interpret the value?
<output type="currency">123456.00</output> formats output using user's settings: https://www.elevenforum.com/attachments/currency_format_cont...
If you want specific country format then you may use lang:
<output type="currency" lang="de-DE">123456.00</output>
Currency conversion is not a subject of a browser.