Should We Revive Extinct Species?

Imagine being able to see a woolly mammoth, the Tasmanian tiger or a flock of passenger pigeons again – it would be amazing.
The concept isn’t just entirely wishful thinking it seems. 
Scientists from Japan and Russia say there may be a possibility of cloning a mammoth from the well-preserved bone marrow of a mammoth thigh bone recovered in Siberia.
The idea would be to replace the nucleus of an elephant’s egg cell with that from the mammoth’s, produce an embryo then place the embryo into an elephant womb for gestation and delivery.
Fascinating stuff, but as the old saying goes, just because you can do something, it doesn’t necessarily mean you should.
As I was considering the number of species sent into oblivion during what is termed the 6th Great Extinction (now), the thought struck me that bringing back these creatures may not be as great as it sounds.
We humans have a bad habit of treating things rather shabbily that we think are in endless supply or can be easily replaced.
Suddenly, the plight of the Tasmanian Devil may not be quite so important or that of any one of thousands of species currently facing extinction.. after all, we could always bring them back when it suited us. 

Or maybe we would bring back something we simply shouldn’t for reasons we are yet to discover.
Perhaps I’m over thinking this or overestimating just how broadly this technique could be applied if successful in the case of the wooly mammoth – but sometimes I think we’re getting a little bit too smart for our own good given we don’t appear to have the necessary wisdom to go with it.
What do you think – should we bring back species that are extinct if we had the ability to do so?