The "pros and cons of Covid vaccine passports" does not mention the two issues about them that most concern me.

I have no objection to requiring a traveler to present a certificate of vaccination along with per passport when crossing a border. But if the system requires the traveler to have a portable phone, that makes it unjust. Portable phones are tracking and listening devices, which is why I refuse to carry one.

If restaurants and other businesses check these certificates, that could require people to have portable phones to enter them. But even if they accept paper certificates, the system could still result in identifying every vaccinated person who visits them. Tracking people's movements creates a database for repression, whenever a government chooses to use it.