Emails: permanent written record I can refer to later
Can reply in my own time
Low labour
Low resource use
Phone call: Times/dates mentioned will be forgotten often
Active demand of time
I don't pick up because that phone number looks weird but also my phone's vibrate function is weak
High labour
High data cost per information
My shrink's office seems to want to keep billing information and past/present appointments secret. (This also seems to be worse in local industry, everything has to be a meeting instead of a two line email)
I think you may be underestimating the labor required to respond to emails on the part of the business, depending on the task and what information is typically needed. I understand wanting a written record of things, but I get a lot of client emails that turn into ridiculous chains because people can't follow directions or things are harder to explain in text or a document is missing and it takes another 3 days for them to reply, etc, etc.
I've had people schedule meetings with me and those meetings come before I've ever even had a chance to see their email because of the volume we get. Then we resolve whatever it is in 5 minutes and don't have to worry about it anymore. I've also had people email me a laundry list of very complex questions that will take much more time to explain in writing and will definitely not be done promptly because I have 5 minutes between other meetings to write out a response to 1 out of 10 questions and it takes me that long to even parse all of what it is they are asking.
There's definitely situations wheres meetings should have been emails, but at least in my position, there's equally as many things that should have been a phone call or Zoom meeting or something instead.
EDIT: Ideally, email is for less complex questions or things that can wait a significant length of time (like 1 - 2 weeks in my position), where meetings/phone calls are for more urgent or complex situations. But this definitely isn't the reality.
I feel like meetings are preferenced way too highly in my workplace. If it will involve a back and forth, meetings are actually faster, but asking "what is the valve on line 3s code?" Does not require a phone call or a scheduled meeting or phone call, and I can busy myself with other things while I wait for the info.