Apple Pay does something called tokenization, and the goal is more fraud protection than privacy. It generates one new number at card enrollment and uses that exclusively. By using a unique account number which can only be issued by Apple Pay devices, it means it doesn't matter if someone hacks the merchant and steals your number. They can't use it without the associated Apple Pay generated cryptogram, secured by your PIN / fingerprint.
Honestly the enhanced security of Apple Pay is underhyped. It's really great.