"Throw out C, D, E since they all sound like B, keeping only A, B, F from the first version. Then add in the other visually- and phonetically-distinct letters:

"Throw out C, D, E since they all sound like B, keeping only A, B, F from the first version. Then add in the other visually- and phonetically-distinct letters: H, I, L, M, Q, R, U, W, X, Y." This encodes region-specific assumptions as part of the code logic. This might even differ due to dialects/regional differences in pronouncation and will fail at latest when it comes to completely different languages (for which one doesn't even have to leave the US, given e.g. the huge Spanish speaking community). I don't know whether Uber Eats is available in other countries than the US, but this would bite them in the ass as soon as they're expanding internationally.