If somebody put the hands in you paper or cryptosteel, he can read and stole your crypto. But if you store your seed in CryptoPlatz Card, he can't ready and stole, because is encrypted.
Yes, but they can't have my coins if I have one or more strong passphrases on top of my paper or metal plate.
CryptoPlatz is encrypted, but if customer used weak password that it can be hacked and extracted by someone who knows how to do it.
I am not saying CryptoPlatzdon't have some advantages, but it's certainly not universally perfect solution.
I guess you could create some campaign or beta testing for this prototype PVC cards, and if everything works fine you could probably collect funds easier on indiegogo.
Problem I have with stainless steel material over NFC chip is that it could block the antenna signal and not work in the real life.