The nato phonetic alphabet one cracked me up. My dude you don't need that, call center employees don't know it, just say S as in Sugar like ur grandma used to.
The nato phonetic alphabet is still useful even if the other party doesn't know it, I've used it a bunch of times on the phone to spell out my 10- letter last name. Saves quite a lot of time and energy for me vs saying "letter as in word" for each letter.