However they should use the non-breakable space separator ' ' less error-prone

I sorta knew that. But it still feels weird for dollar amounts. As 25.000 looks a lot like 25.00 ($25 dollars, 0 cents).

From that document:> and some countries separate thousands groups with a thin space

Thin space (U+2009) is also how you are supposed to do it when using the SI unit system, according to the SI spec. For the decimal separator, the SI standard is to use which of '.' or ',' is customary.

Doesn't make it smart.