If you're me, it's still useful because the ones I make up on the spot aren't great.

"S-T-E-V-E @ gmail.com, S as in sun, T as in taste, ..." "Got it, fpeve."

I dunno, there's a pretty good chance that the one that people spent time and effort designing to replace earlier efforts with the goal of reducing potential ambiguity and for use over noisy connections with expectation that mistakes could cost lives is probably better than what you improvise on the spot