While researching database views related to enterprise geodatabases I was trying to distinguish the difference between the database and versioned views. Is it just the fact that database views with versioned data are considered versioned views? Or are versioned views only considered the fact when a different version other than the root is being used?
The documentation (What is a versioned view) covers this in detail:
A versioned view incorporates a database view, stored procedures, triggers, and functions to allow you to use Structured Query Language (SQL) to read or edit data in a geodatabase that has been registered to use traditional versioning. When you query a versioned view, you can see the data in the base (business) table and the edits that are stored in the delta tables. The triggers used by the versioned views update the delta tables when you edit the versioned view using SQL.
Unlike database or spatial views, versioned views are not used to change the table's schema or limit access to it; rather, they are used to facilitate access to a certain version of a table or feature class. Therefore, you do not specify a where clause when creating a versioned view. As a result, versioned views contain the same columns and rows as the base table they represent.
Database views are "plain old views" as supported by the RDBMS. The documentation also addresses how views interact with the geodatabase:
Database views are stored queries that select data from specified tables. You can define views on database or enterprise geodatabase tables that are not registered as versioned. When used with an enterprise geodatabase, database views can be defined for a single nonversioned table or between two nonversioned tables. Or you can create more complex views that contain subqueries.
This same document also provides a list of reasons to use views and limitations of views when integrating with the geodatabase.