The main reason for MooseX-Types at the time was that since Moose types are global, you have to be careful about conflicts. Your "MyOffset" type for example is not very distinct. Another module could easily have that type itself. So it became best practice to name them "MyProject::MyType" with a project prefix.

So MooseX-Types is there to do the following for you:

• Encapsulate your types into a reusable library from which you can import the types into your current package.
• Provide the types as exported functions so typos can be caught.
• Handle namespacing of the types so they don't conflict.

The last part is crucial here. Since the declared types are namespaced, your type is actually named "myTypes::myOffset". If you use the bareword you don't have to type out the namespace, among other things.

So basically what zwon++ said is right, just wanted to give some context as to the reasons of why it is this way.