Whatsapp claims to be E2E encryption, but it can still submit anonymous("") metadata("") At least they can identify you and your contacts by real phone number, real name and nicknames, and more often than not real pictures; the information can be crosschecked across all your contacts who in good faith provide good information.
There are also bussiness accounts which are really important depending on the location.
It is very hard to put a price to that, but its value is undisputable.
This is exactly my point. I'm sure there's lots of intelligence that Meta can attribute value to, in a complex attribution process, but I doubt that it's as simple as a revenue stream or P&L.