FWIW while comma vs period for decimal fractions is a point of significant variability globally, the use of comma to group digits is fairly uncommon, whereas period is universally understood as a decimal separator even in countries where comma is normally used for that purpose (thanks to calculators and computers). And, on the other hand, space-separated groups are self-explanatory for those used to comma for that purpose. So using spaces for grouping + period for fractions is indeed the way to go to maximum readability worldwide.