No, there is no missed rule, the comma is the only official decimal separator in these parts.
But I can relate to the the OP.
Us here in the comma world are forever converting numbers in CSV and Excel files back and forth so as to display them in a proper number format.
It’s like that darned USB port, you have to flip it 3 times to get it right.
Since it's a big "moat" for parts manufacturing (mainly for defense industry)... I predict the USA will give up imperial units when it's empire finally collapses.
Perhaps in the next few decades as China builds its own economic sphere.
I was about to comment that feet, yards and miles are not imperial measure; but I checked, and WP says they are in fact imperial units. So i learned something today.
We also use apostrophe as the thousands separator, so: 1'234'567.89 which I personally always found much more readable that using commas and dots. Is there any other country that uses this combination?