Have to enable 'Show Items with no data'?

We have a SSAS tablular data model used for Power BI.  When I use fields from a different table that have null values I have to enable 'Show items with no data' so all records are visible.  Being new to Power BI and more familiar with relational data models, it seems non-intuitive to me that I have to enable an option to show records with null values. 

Is this a design flaw with the data model, or as it is a tabular data model this is expected behaviour?  What is best practice for the design of data models in this regard.