One already carrie around a mobile phone that accurately and uniquely identifies one's location on the planet. One pays electronically for goods that allow companies to know both one's purchasing and consumption habits. One's passport is already a 'clever digital certificate'. Everyone who is a member of society has a data footprint - an additional parameter within that data set indicating whether one has been vaccinated is not going to change much.
"International travel is dead until 2022, lets not kid ourselves that vaccine will sort out everything"
Sadly, I very much agree.
Another nuance of the current vaccines is that while they have proven efficacy in symptomatic Covid-19, the jury is very much out on whether they protect against asymptomatic Covid-19 - in fact the limited evidence suggests they do not. The concern around this is that a vaccinated person who suffers mild symptoms or is asymptomatic will still be infectious. Whilst this not a problem in a vaccinated population, it very much is if travelling within a vulnerable un-vaccinated one.