Oh sure, but the context is REST apis, not WebDAV :) PATCH allows two users to update different fields on the same resource at the same time with no conflicts.

Oh sure, but the context is REST apis, not WebDAV :) PATCH allows two users to update different fields on the same resource at the same time with no conflicts. Otherwise, they'd use PUT and the last update would win unless they use something (client-side) such as compare and set.