It is factually better than a vaccine card. Let me tell you why: Getting the vaccine should make you test positive for antibodies. Having COVID-19 should make you test positive for antibodies. Not everyone who gets the vaccines respond well to the vaccines and may not have the requisite titer count to get a positive on the antibody test. Therefore, their vaccine is not good enough. So the best mandate we could have is an antibody mandate: everyone should be mandated to get an antibody test. Based on estimates, between 65-80% of the population will have antibodies if you include the vaccinated people. This is a much better indication of overall protection from hospitalization and death than a vaccination status. Here's why they won't do something like that: it's a much better measure and it would allow millions of tens of millions of people to skip the vaccines. Not what they want for forcing people to comply to unscientific mandates. Note: not all antibody tests are equal. Some have shit reliability. Some are over 99%. The high quality antibody tests are the ones that should be used for this.