One of the main feature of debug mode preferences is the display of detailed views and options active on every Joobi pages.
For instance in the product page, it will show you all the preferences that is currently define and enabled from the admin settings.
When you login as admin from the front-end or admin panel, you should see like below screenshot if you visit any Joobi pages.
The debug configuration is only applicable to Joobi products, it will not work to debug Joomla pages nor any third party extensions.