It enables you to easily use different Corona versions side by side, for example to play with daily builds. See this (https://coronarenderer.freshdesk.com/support/solutions/articles/12000066819) and the ‘(https://forum.corona-renderer.com/ Multiple Corona versions - carefree variant #msg173258)’. Minimum Corona version which can be loaded this way is 5.x. And you have to use the plugin(loaders) from v6 and above in your plugin directory.
Good Luck