Of course, data confidentiality should come first for any company. But what do we see in reality? Mobile operators sell databases, sometimes it seems that even banks spread information about the contact information of their users. If Facebook adapts cryptocurrency payments, it will only help its rating. There previously were much info that Facebook confidentiality = zero, everyone can buy user's password, what r we gonna see if they launch crypto payment?
Privacy is a dream if you are using these services and even if facebook or any corporate come up with their own centralized cryptocurrency, the security and privacy they offer is just a mirage, if you use them then they will come to know everything about your financial transactions and they will have your complete data including your personal and financial details which is highly contagious.