Digital Asset Management (DAM): Integration for Plone

For my personal understanding and the state of DAM's.... What is the purpose of the integration in most cases when connection to a DAM?

  • Browsing selecting and then copying the media into Plone for further use and consumption?

  • Or are there also DAM's that host the media to the outside world and Plone only needs to store a unique identifier / link to the hosting URL?