The name is not only the default label name, but also the name used to identify the measure in the application. It can be troublesome to rename an measure if you have a other measures referring to it by name. Then it is better to use the label expressions are ffor the label.
I usually start off using the name as measure name, but if I need to change it later on I use just to ensure that I don't brake any relations to other measures.
Another reason for using label expressions is when you want to generate a label based on an expression, that can not be done using "Name ".
