Which is tied to your legal name and real address, as per the Privacy.com terms. A chain is only as strong as its weakest link, and unless you register a Privacy.com account with fake credentials, you can throw any notion of privacy out the door.
It's privacy such that the seller doesn't know who you are. Which is certainly more privacy, even if it doesn't provide privacy against legal process, etc.
It would also depend on who Privacy.com shares the link between you and your pseudonyms with. Their ToS/privacy policy mention third party identity verification and fraud prevention but it's not really clear what that means and if it entails de-anonymizing pseudonyms towards payment intermediaries.
