Is there seriously a difference between 0.75 and 0,75?
it makes a huge difference, yes
especially when you get to something like 1.234 vs 1,234
and back to comma vs decimal, it doesn't look like it's tied to the imperial system
"Countries where a dot "." is used as decimal mark include: Australia United Kingdom United States"
"Countries where a comma "," is used as decimal mark include: France Germany"
it seems more like a random scattering between the two than anything else
pretty sure 4/5 of those places use metric, only US in those use imperial (which does kind of suck, yeah - I normally end up converting ~3 feetish to 1 meter)