Only the combination of formats results in ambiguity. Neither format is ambiguous on its own.
Standardization is good, and if someone were to change it should probably be the US given the apparent worldwide consensus otherwise. That doesn’t make either format good or bad on its own.
What I take issue with is people acting like the US format is some kind of bizarro nonsense when it in fact makes perfect sense in terms of matching spoken dates. That is hardly a weird basis for a format.
Each has its tradeoffs, and which set of tradeoffs is better is a subjective matter. I agree that d/m/y makes the most sense for an international standard (if not y/m/d), but to claim that the US format itself is somehow objectively bad is silly.