Yes, I understand, and it’s the same with the Norwegian keyboard I’m using. But the thing is that even if you are on a US system, when you want to enter coordinates, you will have to move away from the numeric keyboard anyway. There is only one symbol on the numeric keyboard and you need two - a decimal and a separator.
That being said, I do not disagree with your wish and it has come up many times in the past. Since one probably inputs a single number (with decimals) a bit more frequently than 2 or 3 coordinates in a row, an option to set the decimal IMO is a valid wish. Whaddyathink, @pascal, one for the heap?