Let's say you have an RSS Feed or any other external data source you would like to use inside your Wix site. Instead of creating a Data Collection and get the data and store it inside a Wix Data Collection it would be cool to add a virtual Data Collection. This virtual collection of data would be an external API that returns data in JSON.
So when I create a virtual collection I just point it to the external API and it will automatically create a virtual Data Collection inside my Wix site. I can use that virtual collection as a standard data collection.
I can create repeaters, query it and more. I can also set the cache level on it so it will remain static for let's say 2 hours and then the data will only be refreshed every 2 hour.
If it would also be possible to add hooks to it like a standard data collection we could modify and play with it inside our site.