You need ONE wallet and then you can use it for all sites. It's much, much easier.
Setting up the wallet doesn't need to be more complicated than setting up a card with Apple Pay. You don't need to understand the underlying technology to use it in millions of stores.
Today's system is like setting up Apple Pay every time you need to buy something in a store you have not visited before. It's a horrible user experience.
Today's system may be complicated, but users understand it and are used to it.