For me: phones cut off an entire avenue of information (body language) and make it harder to know if someone is annoyed at you or when you should talk. Also I’m not a fan of talking to strangers, but it’s not as bad when they’re in front of me.
You're talking to a person to get a service, you're not going to socialize with the 911 girl. You are calling to order a pizza, not calling to impress the person in the other side of the phone.
My buddies and I used to have board game nights. When we inevitably ended up ordering food, people would start pitching in the money just so they didn't have to call. (As in yes, the guy who made the call got to eat for free.)
On a call, I need to be constantly available and have that stupid mask of happy, springy person.
On text, I can chill out. Modulating text is easier and also I don't really need to do this that much, because people can't read tone hints in text anyway.