They're doing it to skirt GDPR laws. When GDPR passed, all users were automatically opted out of personal data sharing, targeted marketing, etc. With ZuckCoin, they're going to pay users a small amount of coins to use the site, but in order for users to be eligible for that they'll be required to opt into all of the personal data sharing stuff. And since it will be considered a monetary transaction, Facebook will be required to keep the data from every transaction for 10 years for tax purposes. People won't even be able to ask that Facebook delete their data because they'll be required to store it for 10 years.

edit: If you want to listen to the explanation in more detail, Meanhash explained it on a recent episode of the Hashr8 podcast: https://h4shr8.libsyn.com/meanhash

https://www.reddit.com/r/CryptoCurrency/comments/bx9dik/face...