Why is it important I install Group Gator from the Google Apps Marketplace and not the Add-on store?

Installing from the Google Apps Marketplace is critical because it allows for Group Gator to obtain the ability for non-admin delegated managers to borrow the necessary authority to manage groups they are not the owners of.  Purely installing Group Gator from the Add-on store will not grant adequate permissions. End-users e.g. delegated group managers should be the only ones accessing Group Gator from the Add-on store.