Why is auto-reload on code change only for debugging with Gunicorn?
The reload flag can be used in production and basically it does the same thing you do manually when restarting gunicorn.
The basic reason not to use auto-restart in production is that you are compromising the reliability of the service to third parties, without any possibility of control from your part.
Imagine that your service is continuously updated with new code. Some of it might be buggy and break the user experience and you would have no way of preventing that. On the other hand, if you update the app multiple times during a day, your users would be potentially losing data/having a bad experience multiple times during the day.