Wikidata it is important to be able to edit Wikidata itself while working at the same time on a Wikidata client. The presenter wanted to understand if this is an issue that needs to be addressed soon.
When you will be using Wikidata on one of the Wikimedia projects, you will typically use one user on all projects. This user is authenticated once when he signs on with his global user account and, this authentication serves him well when he works on other projects.
This will work well for Wikidata. The only issue left is that they also want to be usable and editable for users who use Wikidata from their own server. This however is an issue that they do not have to solve immediately.
There is existing functionality like OpenID that may provide a solution for this. It is great that the Wikidata people consider how the data can be used from outside the Wikimedia Foundation. It is wonderful that they provide a use case that makes a case for implementing OpenID.