Yes, the date passed to the variable is in the format DD/MM/YYYY.
A great explanation. Still a little puzzled by one aspect.
The date format we see is effectively the text element of the underlying field value: dual(text, number), and this is the textual representation of the underlying number e.g. 03/06/2019 is the text interpretation of the number 43616.
Does the dual format not apply to variables?
Also, why is there no need to use Date# in this case.
This is because you don't store it as a dual and Qlik doesn't recognize the 43616 as a date.
When Qliks engine recognizes a date automatically, a Date# is not needed. A Date# is used to interpret the dates that Qliks engine is not recognizing and often used as a save option (Because versions of Qlik can differ in handling this). For example, 03062019 is a date, but Qlik does not recognize this and for this you need Date#.