A. Real time sync between salesforce and Postgres B. Bidirectional sync, allowing data to be written into SFDC C. Near Real Time Sync between Heroku Postgres and Salesforce D. Displaying data from an external data store via External Objects
Heroku connect makes it easier for you to build Heroku apps that share data with your salesforce deployment. Using bi-directional integration between Salesforce and Heroku Connect, as well as connect unifies the data in your Postgres database with the contacts, account, and other customer objects in the Salesforce database.
It can also create apps that extend your data to your customers. It allows you to create a flawless experience while keeping all of the data in Heroku Postgres. Any data in Heroku Postgres can be integrated into Salesforce.