Angus, you raise a very good point. The intention of ORCID is to look at all contributors to scholarly works. In practical terms the question is really what scholarly works have an identifier so that we can attribute them to a contributor. Having an ORCID really only makes sense if you can connect the person to the work. That is certainly easy for publications (CrossRef DOI) and will be for research datasets (DataCite DOI), but more difficult for other contributions. It would be good to also have a unique identifier system for presentations and posters at conferences, for patents, for teaching, etc. but we are not there yet.
Kind regards, Martin