The 2006 CIA Factbook stated that the "US is the only industrialized nation that does not mainly use the metric system", (in addition to non-industrialised Burma/Myanmar and Liberia).
This particular case is not English vs. Metric, but rather lack of cohesion in the metric system.
English: Use commas for separating thousands, use periods for decimals.
Metric: Use spaces for separating thousands, use periods OR commas for decimals.
In this instance, the English approach is obviously the superior one, as spaces are more confusing to use as a delimiter than commas, and there should only be one way to write decimals for consistency.
I´m european and the natural way for me is period for thousands and commas for decimals, although I´m aware of the imperial way, with commas for thousands and periods for decimals.
Another important difference is that in Europe we understand a billion as a million of millions (10^12), not a thousand of millions (10^9). For us, a 10^9 is a miliard. Luckily I´m also aware of the use of billions for 10^12 and whenever I read it on a US or UK text I understand correctly. Otherwise, saying that there are 7 billion people on Earth would be an extreme exageration...
There is some other system that uses periods for thousands and commas for decimals - the exact reverse of what you've listed as the english convention. I always thought it was a european convention. It makes more sense than what you've listed as the metric convention.
Indeed, and that is what I've seen from many Europeans.
However, I think that must be a convention from before the universal adoption of the metric system by the EU, as the 22nd General Conference on Weights and Measures (held in 2003) declared that the symbol for decimals should be "the point on the line or the comma on the line".
i.e. the official metric system symbol is period or comma, regardless of what actual Europeans use.
>i.e. the official metric system symbol is period or comma, regardless of what actual Europeans use.
Regardless? Those (and mainly comma) is exactly what Europeans use. It's not like there is some other symbol besides those too in use for that purpose.