To answer your original question:

A question: Why do you serialise objects?

Three reasons:

1. Debugging - quick 'n' dirty view of the current objects state.
2. Persistance
3. Copying - soemtimes a quick freeze/thaw cycle is the simplest way

As to your other comments, I tend towards having serialisation be the responsibility of the class, since it gives you more flexibility.

This doesn't mean that you have to write a brittle serialisation method for each class - there is nothing stopping you using Storable within your classes freeze/thaw methods (note: "using" not "inheriting from" - inheritence is overrated :-)

This gives you flexibility (you can change your serialisation method on a class by class basis if necessary) and simplicity (common functionality sits in the serialisation class).

The "problem" with inside-out objects is that the "simple" case - dump all of the attributes - becomes hard. You can't just throw $self at Storable::freeze in your classes "freeze" routine.