Okay but my pharmacist has a WhatsApp business account you can communicate on. I would not call such a conversation non-personal, instead it is super personal. But based on what Facebook is saying this wouldn't fall under the "personal" category, and that is worrying.
Not specifically. I assumed the distinction from the two below.
"We offer end-to-end encryption for our Services. End-to-end encryption means that your messages are encrypted to protect against us and third parties from reading them. Learn more about end-to-end encryption and how businesses communicate with you on WhatsApp."