Have you been to any places that have asked for either a negative test or a Covod pass?
I've done two. Neither actually checked the details, I just waved my phone in front of them and they waived me through.
Obviously at that point it was voluntary on the part of the organisers, but is it really likely to change once compulsory.
Plus, you can record a negative test without actually doing one, so any one who wants to cheat the system can easily do so.
I don't like the idea of "papers" but accept that something needs to be done to try and keep things moving. I can't see how this is it though.