In Release Deliveries from Label to DSP

Yes it is.

While in most circumstances such a message is non-sensical – after all it instructs the DSP to ingest a set of releases but to not make a single one available. However, there are scenarios where this does make sense, e.g. when the street date of a release is near but the precise details of the Deal have not yet been finalised. In such a scenario the DSP is given time to prepare the Release (e.g. by encoding the resources, creating pre-views, etc.) before the Deal arrives.

As such a NewReleaseMessage does utlise resources at the DSP, a label should only send such NewReleaseMessages when it expects to follow up with Deals in the near future.

In feeds to Metadata companies, chart companies and Music Licensing Companies

Yes; such feeds typically do not contain Deals.