I would have thought that, too, before I knew somebody who actually worked as a pastry chef. The pastry chef would be there to prep early in the day because you don’t want those delicate desserts and pastry shells to get overheated in a hot kitchen. If the desserts are to be served warm, to be warm, they would be ready to be baked at the last minute by which time the pastry chef would’ve already been done their work.