Purpose of a namespace
Namespace primarily helps you organize and manage your metadata. For example, it could help you:
1. Identify custom metadata against OOTB metadata
2.Identify a metadata’s source: when metadata flows-in from from multiple 3rd party systems
a). In such scenario, you could easily identify the source of metadata, by mapping a namespace against the metadata’s scource.
3. Filter what should be written on to an asset binary by Metadata Writeback Workflow. The DAM metadata writeback workflow would only write a metadata that has a namespace.