In the EU the comma is used as decimal point and the dot as grouping opreator..

That is not exactly true. The EU is a political entity which has come about in the past few decades, and it does not have any impact on how people write numbers (at least, not yet; now you mention it, an EU number-harmonization directive is exactly their kind of thing).

There are many countries in Europe which have not signed up to being part of the EU but which use a comma as a decimal mark and dot for thousands separator. And the UK and the Republic of Ireland are both members of the EU but use dot and comma the same way as in the USA.

To help avoid confusion between the different cultural practices of using commas and dots in numbers, the SI and ISO standards say that neither should ever be used as a thousands separator, which should instead be a thin space. The trouble is that it's very hard to persuade a computer to produce such a thin space (especially in a fixed-width terminal window!). More details on this page, Attack of the Thousands Separator.

With the exception of the UK (any others ?) which is EU but does numbers the US way (except billion which here is a million**2, or at least it used to be)

Cheers,
R.