"Ehm, I wanted to tell you, you know, eventually (...)" <- this are three to five seconds I'm not getting any information, but if it would be text, my brain would skip this unimportant part instantly. This is why I never listen to voice messages. If it's important to be expressed with your voice, then call.

You can read fast enough to churn out information, but you need to wait for every second to digest the information in a voice call. This can happen, but I can reread the message or just parts of it fairly easy. With voice messages it's getting annoying when you need to rewind to a specific part of it, especially if the message is 2-3 minutes long.

And there is also the audio quality and background noise, but it's a different topic.