I was talking about spoken language, not the existence of initialisms per se. Though I'd wager they are a lot more prevalent in written American English than in most other languages as well. Nobody else would think of inventing an initialism-euphemism for body odour (which I guess already is a euphemism for "smell" for example. Or "significant other".

By the way, QED is just a calque from Greek. (Like most things Roman...)