To be honest, this idea isn't new, it's just cos PM talked about it at the rally and Razer responded and got a reply tweet. Look, anyone in tech who's been talking about a singular e-payment system for years would know this isn't novel.
New payment must not have the need to issue receipt or wait too long for approval. The user activates phone to scan QR code, a tick appears and off he goes.
LKY would have say let the market decide rather than force a single system. The weaker players will drop out leaving the few strong ones left. If you force a one system and if that prove to be the wrong choice , you end up with no backup option.