No, that's the weakest advantage, I've cited others. For instance, being able to rename the namespace is very important if you're using third party libraries which may have conflicting names.
Half the reason for Wolfram Language's large standard library is that you should almost never need a third party library of any kind. If there was a third party library that was particularly useful to typical Mathematica use cases, Wolfram would just put it in to the standard library...
