AppEngine docs recommend command-line flags instead of app.yaml file elements

Question

In the app.yaml documentation, Google makes the following recommendation of number of times:

"The recommended approach is to remove the ELEMENT NAME [e.g. application] from your app.yaml file and instead, use a command-line flag to specify your ELEMENT NAME [e.g. application ID]"

Unfortunately, Google doesn't explain why they recommend this.

In my opinion, an informative app.yaml file is much more helpful than deploying an app with command-line flags. Can anyone explain why Google makes this recommendation?

Answer 1

I think mainly because they are slowly moving away from the appcfg.py, to start using the Cloud SDK instead, where application is not supported. You can set your default application so you won't need to use command line all the time.