This feature will only work on premium websites, it allows you to "lockdown" your store, so nobody will be able to view it, or buy anything. This may come in handy when you are still working on your website and you don't want any visitors to buy things while you are working.
How to enable Maintenance mode?
1) Go to your CraftingStore panel.
2) Click on the "Settings" tab in the sidebar.
3) Select "Webstore"
4) Set "Maintenance mode" to "Yes" and update the settings.
After this, your website will be locked down, and nobody will be able to look at it, or purchase items.