Also it would bring extra limitations if Alice NEED to receive a big quantity of payments in a short period, for example in the scenario of Alibaba Nov. 11 event (link).
This! Amazon could have an account and dozens of people may want to pay at the same time, especially during Christmas session!
They can have multiple accounts.
That sounds more than a hack than a solution.
Would it be not troublesome for the merchant and the customers to care about that?