Also what I thought. If this starts becoming widely used, then Google would be essentially getting a share out of the tip that readers would be giving to publishers, only for the service of "not showing ads and redistributing money".
I think sites are still free to offer "register and pay us to see no ads" model, like many already do. Implementing that will cost them money too (especially dealing with accepting payments), or they can just use Google's implementation and just give Google their bank account information, Google takes care of the rest.
I think that the ideal here is that something like this manages to supplant AdSense as Google's main actual business.
But the issue is that for AdSense, Google solicits ad buyers, removes scams, and distributes traffic. If you're paying to not see ads, it's unclear what good Google is doing compared to just paying the publisher.
It's not zero-value, since the transaction costs of paying every publisher are crippling. But there's no definitive reason to look to Google for this value.