Coronapass for Apple wallet from the official green pass certificate

That's a different discussion, many EU countries require proof of test or vaccination for certain activities (travel, restaurants), at the same time handling PDFs on the phone can be quite inconvenient.

I think this is an interesting solution where the data processing is transparent, I don't need to install another app that might do things I would not be ok with and comes at 0 cost, compared to the amount that is being spent by some governments with very little to show for.