[saithound]

Certain orders are grammatically more convenient in certain languages, but that's not the same sense of practical as the one referenced above: cf. "inches are more practical than meters because they have the same spelling in American and British English", vs. "inches are more practical than meters because they're human-scale units".

Sure, date order may be decided based on accidental grammatical features of the target language. But that just reaffirms that "practicality for the common man" is rationalization.

Naturally, the written convention need not affect pronunciation: in the case of numbers, the world standardized on decimals with place values increasing from right to left, but most languages retain their own idiosyncratic ways of naming/reading them This causes negligible friction in practice.