I think the devil is in the details. The claim `Calibra will not share account information or financial data with Facebook,
Inc. or any third party` is followed by `without customer consent.`. From reading through the document you linked, the infrastructure will definitely be there to support the sharing of any and all data. Considering Facebook's history with getting "consent", I am willing to bet that they will take every chance they can get to manipulate users into giving such "consent".
“When Facebook notified the acquisition of WhatsApp in 2014, it informed the Commission that it would be unable to establish reliable automated matching between Facebook users' accounts and WhatsApp users' accounts. It stated this both in the notification form and in a reply to a request of information from the Commission. However, in August 2016, WhatsApp announced updates to its terms of service and privacy policy, including the possibility of linking WhatsApp users' phone numbers with Facebook users' identities.”
"We will implement cold wallets and multisig wallets that allow Libra users and association members to add extra security for their Libra coin and Libra Investment Token holdings."