Note in the CDR you might have date of birth and sex, since those data points are relevant for clinical use.
Though some may say, it is also important to know the social, economic and environmental information for clinical use, which is true in some contexts like occupational medicine, so some might consider to put that info in the CDR, though having that in the Demographic Data Repository doesn’t mean clinicians can’t access the data, in fact they can, but that the data is managed separately from the EHR. Which has architectural and technical considerations, but doesn’t affect data accessibility.
In my experience, in the long term, it is better to put specific data in the specific system that is designed to manage that type of data. Though some people for some reasons put everything in the EHR. I guess each approach has it’s pros and cons. For instance, for a micro-service architectural approach, each component should have a specific responsibility in term of the data each component manage, the goal is to avoid duplicating data in different repositories and having one source of truth that other components can use, then a Clinical Repo and a Demographic Repo, each have a specific responsibility, and external apps can access the data from both and link the data together to be displayed in a clinical environment.