Waters can (or once could) cook well enough that she filled in as chef for six months in 1972. I don’t know if she ever made a pizza herself, but the vision for the cafe and its pizzas was entirely hers. There was nothing like it in the US in 1980. Downstairs and up, Chez Panisse was still the only restaurant in the country that had ingredients like you could find in France and Italy. In those days she still had to have foragers to be able to do it.
She has always given the chefs who work for / collaborate with her a lot of freedom, but to some extent they’re always working within her vision. That’s why the restaurant has stayed so similar in style over so many years and personnel changes. Her role is something like the artistic director of a theater company.
Puck had some talents but he had little or nothing to do with Spago’s pizza program beyond knocking off Waters’s ideas (he even hired the same German bricklayer, who didn’t know how to build a proper pizza oven) and hiring LaDou. Puck wouldn’t have found the ingredients that were essential if not for Waters hiring foragers to develop sources such as Chino Farm.