If there is back and forth required then voice just isn't the way to go. It's too fast for that. This is why email always wins out over voice.
I think what's really going on is that people who grew up analog don't see textual decisionmaking as "real", and need a familiar voice call to make things feel "official".
For me, my team is mostly +15 or +8 hours from me. So relying on voice is just impractical.