Direct Query - clarification on time intelligence

Hello Community  -  Direct Query seems quite limited except for any very nuanced use cases.    Aside from the other limitations, one thing I am trying to clarify is the ability to use time intelligence features.  

I have a data set that includes a date table and time intelligence seems to work.   Does that make sense?   I've also tried adding a date table to a direct query data model  (that did not inherently contain a date table), and time intelligence did not work.  

• No built-in date hierarchy: When importing data, every date/datetime column will also have a built-in date hierarchy available by default. For example, if importing a table of sales orders including a column OrderDate, then upon using OrderDate in a visual, it will be possible to choose the appropriate level (year, month, day) to use. This built-in date hierarchy isn't available when using DirectQuery. If there's a Date table available in the underlying source, as is common in many data warehouses, then the DAX Time Intelligence functions can be used as normal.