method delegation in TextWithDash

Here is a bug report related to the output of setp(axes().get_yticklabels()),
the complaint is that you can set the size but size is not listed.

The reason is that TextWithDash has a Text object attribute and delegates most
of its methods to that object via __getattr__ and __setattr__. Can anyone
tell me why this approach was favored over deriving TextWithDash from Text?