Yes, Data Assist 3 is a part of Data Bridge.
Data Bridge is Data Assist 3 with the following other extensions bundled into one installer:
--CSS Button Styler
--CSS Form Builder
--Digital File Pro
--Dynamic Web Charts
--Validation Tooltips for Spry
By Bundling the other extensions into Data Bridge, the new Data Assist create pages wizard allows better integration. It allows you to use HTML Editor or file upload fields in your project from the wizard for example.
Also the new wizard allows you to save your application settings asa preset and can create the database table for you.
There is far more under the hood than just repackaging existing extension.
see this page for full details including a feature tour: