AutoApps is a licencing verification for in-app purchases. All in-app purchases are done through AutoApps and AutoApps acts as the licence for them. You will also need AutoApps if you subscribe for access to his plugins and Alpha plugins, as again it will act as the licence for them. This is handy, as AutoApps also serves as a central Command Hub for other plugins of his.
Apps bought directly from Play do not have this requirement.