Creating multiple BPS_Content databases for the system is very helpful in terms of scaling and system performance because when creating a new BPS_Content database, the data tables (wfelements, wfelementdetails, wfhistoryelements, securities, etc.) are empty and the data for them registers anew.
In the case of applications, you decide on which BPS_Content base you want to create the application and develop it on that base.
You have to create the base from the installer - give the appropriate permissions and in Designer Studio switch to the new base and create the application on it.