vaccine passports are a band aid solution to the fact that so many people in the country who should be vaccinated aren't. if healthcare in the country was remotely decent, the issue not insanely politicized, and people reliably knew they could get the time off to take em we wouldn't need passports at all.

if we do them they should be a physical thing, for the reasons you state. but yeah in this country there's millions who the people charge are perfectly fine just falling through the cracks, which they've made clear over and over again