This sounds like what I saw when i tested it with another free facilitator, that one wasn't publishing the transaction to the network. I suspect that the current one, payai also may have occasional troubles posting the transaction, though I do see 4 cents dropped to the account since poating, so the thing works at least for some)
Coinbase facilitator would've been more reliable I thunk, but it requires a registration, kyc and all that jazz which I don't want to bother with)
I think the main issue for now is how fragmented the whole ecosystem is, it was sych a pain fo me to test the thing, particularely to get a small enough amount to a wallet with which I can pay using this protocol. So it is just very unlikley that an avarage reader will have a funded wallet they can pay with I think.
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.
Having options is always a good thing, but trying to make a test payment I myself saw how far away this thing is in terma of encountering a user with a funded wallet on correct network. So I actually agree, it won't replace ads foe a long time if ever.
This is all Firefox's implementation of the client. In the dropdown it shows wallets that it sees as available. I was able to test with coinbase wallet, for you it seems like coimbase alltogether is blocked, yes, but also, for example when I install Metamask extenaion - it becomes available as an option, so you can, in theory use whatever crypto wallet is available in your country. But yeah, as the top comment says - the legality of the whol thing is questinable.
The protocol itself only seems to define only the payment related negotiations. The author is free to implement some sort of preview themselves, though the full content should be on a separate page in order to use the browser's built in x401 client implementation.