Banksy Rat Destroyed in Prahran

So another of famed Banksy's works here in Melbourne has been destroyed, with a stencil of one of his Parachuting Rat's being drilled right through in Prahran.

The cafe whose wall it was on had got some tradies in to undertake some work and they drilled through the middle of the artwork which has been there now for close to a decade. 

It was the third Banksy piece in Melbourne lost in two years. Vandals damaged one in Fitzroy last August and council workers painted over a Banksy in Hosier Lane in April 2010.

But should we care? Is this a loss of a priceless piece of artwork that should have been protected? Or is it just like any other piece of 'street art' - impermanent and not needing to be conserved?