The auto-warming switch (located at the back of Goldie) allows you to turn the auto-warming feature on and off. Here are a few scenarios where turning it off make sense:
Maintenance mode - if you’re not planning on baking anytime soon and you are just maintaining your starter, then there’s no need to have your starter rising at top speed. When you are keeping your starter at room temperature, you can feed it less frequently (typically one feed/day), and save flour.
Your starter got ready before you are - If your starter has peaked before you’re ready to add it to your dough, you can turn the auto-warming off to keep the peak for longer.