It does actually, because not all vaccines require the same amount of doses and if you were infected, that's a completely different story too. Different cities

It does actually, because not all vaccines require the same amount of doses and if you were infected, that's a completely different story too. Different cities also have different timespans after infection or dose after which you can start all the fun activities (and sometimes it matters per activity). For example, the nightclub might require 7 days after the last required dose for vaccination or 14 days after the last negative test after an infection, but other venues might only require 7 days after the last negative test and 14 days after the last dose. In addition to that, legislation may change, so your time limits and dosage limits now all change and future vaccinations might require more doses. Either way, the bouncer doesn't get to see any of this. They only see your name, check your ID if it's the same name (which they have to do anyway to check you're 16 for alcoholic beverages and curfew) and then wave you through. The apps I've seen in use by people who check the vaccination QR code only give you an OK or NOT OK signal, once you've setup the type of limits you have to obey.