Using comma would probably caused more problems as it is a decimal separator for those languages. My excel also uses semicolon in formulas instead of comma when separating parameters. Some VBA scripts break when using different language settings and some forumilas don't translate automatically to different locale so they just give an error. Overall using excel in different locale setups is annoying.
Best separator I have used is | as i have never seen it in the data as an input. Comma and semicolon both have caused issues in the past for me as they might pop up at wrong places.
Thats not really true at leat according to aircrash investigation shows. Crew can make mistakes hours earlier that might lead to a crash or accident later. Mess up something during preflight checks and that can be the issue during later stage. Flights are long.