The generation is running while you login, so this appreciable decreases wait time from idea to app, because by the time you click through the login, your app is ready. (Vibes DIY CEO here.)
If login takes 30 seconds, and app gen 90, we think this is better for users (but clearly not everyone agrees.) Thanks for the feedback!
Put it before letting people enter text, rather than once they've entered text and pressed the button, and people won't feel mislead anymore.