I did not get it how it could be used for a _static blog_.

>…the paywall fetches the content behind the scenes, and since our response is JSON rather than HTML it has nothing to render in place, so it navigates to an in-memory object URL created from the response. The protocol itself is pay per use, so every time you hit an API - you will be charged.

So it can't be used to 'unlock' a paid article forever? You can only read it once, and if you closed the tab, you need to pay again?

Yeah, it doesn't unlock content forever, the protocol is made with assumption of payment per use. I haven't tried to present the same payment confirmation twice, but reading about it I assume it will fail. In this PoC the browser's ser opened content in memory as a separate tab, but it is a side effect, bot a feature. So you are right, it's not usable for tracking subscriptions in any way.

There is a description of an access token, so it looks like you'll have some time to access a page. Anyway, this is more for bots. If you want this page so much, just print it to pdf.