Having come from a military background where using that is second nature, I'm constantly surprised how rarely I meet civilians who understand it effortlessly. When picking up a package I say "the code is Oscar Foxtrot three-fife" and you see the person processing for a long time to extract the first letter of the word. I've started saying "OF, that's Oscar Foxtrot, 3-5" to help them out.

In other words, asking a customer/consumer to be able to recite something in phonetics is not realistic in most cases.

Fortunately the code already takes this into consideration and removes ambiguous characters.