Can the JCR of an AEm instance be used as a central Db and can it be accessed remotely in the same manner as with a Relational DB?

I have some assumptions regarding JCR and AEM, I am not sure if they are correct

Assumption 1) When setting up an AEM server, it creates a JCR db. 

Assumption 2) All the meta data about the application is stored in the JCR nodes and properties.

Assumption 3) When the CQ tools such as CRXDE lite and Web Console are used the structures and changes are comited to the JCR.

Assumption 4) When querying a remote relational database the data returned can be stored in the JCR rather than kept in the OSGI.

A Question based on my assumptions (if they are correct).

Can the JCR of an AEm instance be used as a central Db and can it be accessed remotely in the same manner as with a Relational DB?