It wouldn’t be used directly for transactions because that is (IMO) an incredibly unwise idea for a pub/sub protocol since there is zero privacy. That’s not what the pub/sub protocol was invented to do and I wouldn’t be crazy enough to try and make it do that.
I’m actually only proposing its use as an open standard to BROADCAST inventories and/or changes in those inventories. Those changes would only be allowed to be broadcast by authenticated parties to prevent too much data being sent out at once.
Each item’s metadata may contain links to the url of that item in the vendors web store/instance but it would never actually be used to directly execute a transaction. It’s like trying to get a train to fly. It’s just not designed for it.
The only decentralized payment technology that could or even should be paired with this technology would be a very robust cryptocurrency technology like Cardano, IMO. But I think it wise to work on the inventory broadcast aspect because crypto has such a bad reputation at the moment and I’d hate to mess with an idea while it is on the vine.