When element names of days are serial date numbers, it is much easier to make calculations regarding time, e.g. lead times and due dates. You can simply add or subtract numbers of days from the element name. Serial date number as an attribute is not enough, since you must be able to refer to an exact element with the result of your calculation.
I understand that it's possible to manipulate date format in rules, but I find it easier to have serial date numbers as element names instead of manipulating the format for calculation in every corner.
It is difficult to create a dimension like this without a good source table (or help from Jedox dimension editor, potentially). Format yyyy-mm-dd is needed as an alias, of course.
