Mobile phone replacement is driven by technological innovation, and blockchain technology is such a slogan.
If the blockchain mobile phone can really carry the mature blockchain technology and become a veritable blockchain mobile phone, it will usher in a milestone of innovative technology for mobile phone development.
It would make more people be aware of cryptocurrencies but then I don't know how special it would be or how it would differ than just have an app for wallet. Well, for one thing, you have your private key so only you can access it as long as the only one who knew the key but then it would become a target as well for those snatchers because they knew that you have a wallet or funds in it. You even keep your hardware wallet in a safe and now, you openly use it and a possibility of being stolen from you.