Is it poor advice though? I don't think the article is suggesting to skip designing a nice landing page -- the article is saying that customizing the _login page_ is not worth the effort, which I agree with.

I can say that at my last company, redesigning the login page was bottom of the stack of things we wanted our first designer to work on. We just had a centered "Login with Google" button, our logo, and a email + password form. What else do you need?