Apart from the technical implementation I'm surprised the writeup didn't catch the flaws in such a setup.

The notifyer has no obligation to actually notify correctly. They can spam some advertising site or malicious site.

The notifee (?) has no way of checking that the notifyer has fulfilled their promise.

For example I could say 'let me know' when an update on the new cheese factory happens. Then the wait is too long so the notifyer does a 'semi fulfillment' of the promise. The notifee clicks, is disappointed and has nothing more to vote with since they never had something like a subscription in the first place.

This criticism basically boils down to "what if the site is a bad actor/incompetent", which I guess is a legitimate concern, but would be just as meaningful of a criticism against basically any feature I can imagine. Alas we continue to have useful interactions with third parties despite this.