Explanation/Reference:
Label only is a tag that you can apply to a member to indicate that :
* you don't want to store data.
* the Members do not have data associated with them.
Use Label Only for member like Scenarios, Ratios, or Drivers, members whose sole purpose in life is to organize the dimension and hierarchy.
Note:
Although a label only member has no data associated with it, it can display a value. The label only tag groups members and eases navigation and reporting. Typically, label only members are not calculated.
For example, in the Measures dimension, the member Ratios has three children, Margin%, Profit%, and Profit per Ounce. The member Ratios defines a category of members. When consolidated, Margin%, Profit
%, and Profit per Ounce do not roll up to a meaningful figure for Ratios. Hence, Ratios is tagged as label only.