Do Europeans use 1.000 to express "one thousand" rather than 1,000?

Factual Questions
21

There is only one date/time format, ISO 8601, and we keep it holy.

For numbers, for display I would format them with a space every 3 digits, and a decimal point, if required. No spacing after the decimal point, not sure why. But that is the convention.

For numbers in programming, no spaces, just a possible decimal point if required.

22

True enough. But the decimal “point” can be either “,” or “.”.