Sonification versus musical metaphors?

This video explains some of the frustration I've had with arbitrary sound choices.

For me the question first arose when numerous friends shared this video with me:

I understand the tree rings are triggering the piano but it seemed like sleight of hand when they suggested I was hearing the tree.

Then there are the contact mic apps that use the sound source to trigger a sample. Again it's a somewhat arbitrary process to suggest the object being struck is creating the musical result.

I think sonification is an interesting process but one that would be better described as a musical metaphor.