Some thoughts:
– the automatic option is a weird one because you have no idea what will happen – this happens: it creates a new project for the Google account that is logged in the console (better not logged in with different credentials) and within this project it adds the app engine setup
– when you delete the container it (of course) does not delete the app engine application – so do not forget to disable and delete it – it also does not delete the project
– the manual setup is not so manual at all – you create the project the yourself (which is far better) – then you use the gcloud cli tool to run a bash install script, which ask you some config question – 4m and you are done // the manual setup is basically the better automatic setup.