Virtual entities allow you to render data in Dynamics 365 that isn't part of the Dynamics 365 database. Previously, if we wanted to show data from outside of Dynamics CRM, we had to develop complex custom integration, but now we can easily display custom data in Dynamics 365 using data providers. Data that's available under virtual entities is read-only and for display purposes. Virtual entities have limitations; for example, they can only be used for organization entities, which means you can't utilize the user-owned entities' security features in virtual entities. However, you can utilize an existing calculated field for any calculation. This must be done in external data sources, but this is still a great feature from an integration point of view.