Lol, are you serious?

If that comma would be a decimal separator, there would be 3 digits for the decimals. There are very few currencies using 3 digit decimals: Arabic dinars and Oman rial. US Dollar is not one of them.

https://en.wikipedia.org/wiki/ISO_4217#Active_codes

Also:

Traditionally, English-speaking countries employed commas as the delimiter – 10,000 – and other European countries employed periods or spaces: 10.000 or 10 000.