I've noticed lately that some digital releases are only available for streaming or download. The only way to express this currently is through associated links.
What I propose is a sort of tiered restructure of the medium format, something like this:

• Digital Media
  • Digital Media (Streaming only)
  • Digital Media (Download only)
  • Digital Media (Streaming + download)

This guideline will be needed if this ticket goes into effect:

• If a release is available for both streaming and download, do not create separate release entities for the streaming and download versions. (Exceptions can be made if there are other differences between platforms, e.g. artwork or audio mix.)