Comirnaty had hundreds of millions of doses administered so far, and maybe - maybe - one woman died of myocarditis. This is nothing to potentially hundreds of thousands of prevented fatalities, much less the unpleasant to severe bouts of Covid-19.
Why is it riskier and to whom?
Nor does it actually prove any immunity against disease. You can only assume that these antibodies probe prior contact to the virus and that this prior contact resulted in a robust response. The strength of the immunity cannot be inferred from such titres...
It can have false negatives, making people needlessly take a vaccine, so everyone should take the vaccine in the name of equality?
Vaccine certificates neither prove you actually got the vaccine (though highly likely), nor do they prove any immunity against disease (though fairly likely).
With this level of arguments, I can argue noone should be permitted to take the vaccine.
You probably can't understand (and don't want to) why that is not the case for people who got infected at some unknown random point in the past and with an unknown, random variant of the Virus. And I don't care to explain it to you.
And you probably also don't want to understand why those lab tests aren't designed, regulated or approved as a proof of immunity. To be rigorous enough, probably every single lab would have to do control studies to find out if their tests predict immunity against reinfection.
Otherwise you're just arguing with double standards trying to console insecurity.