Dimension Role-Playing Bus Matrix

How come in a bus matrix, none of the dimension roles are indicated (e.g. only date dimension instead of begin date and end date "logical" dimensions)? Wouldn't this help with the design of the OLAP cube?

My $.02....

The Bus Matrix is not intended to design the cube (or reports).

The Bus Matrix is intended to be used as part of the Dimensional design process. If focusses on business processes (facts) , business context (dimensions) and their logical relationships.

More detailed design criteria (SCD definitions, hierarchies, helper/bridges etc) are defined during later design stages.

Technology specific design elements (e.g. cube designs, report designs) come even later in the design process.

Thanks, that makes sense.