Mmm, as excited as I am at the idea of prehistoric species coming alive, there's quite a few issues. The animals could never live in the wild as they would distrupt the 'balanced' ecosystem (as balanced as it can be with humans constantly mucking with it).
The only reason I can see for this research is the sake of being able to do it. That's...
Possibley the new animals could be used to research diseases and random stuff, but that means you're breeding animals to experiment on. Depending on the experiments it has the potential to be ethically wrong.
I would prefer if they used this method to ressurect animals that we humans have caused to go extinct due to our own selfish needs. However... I'm not sure how they would do that...
Devolve a close reletive of say the Dodo till the animal they produce is a common ancestor, and prey that animal may in the rare event evolve down the route of the Dodo. Still the animal would never be able to live in a real ecosystem. It would forever be in captivity.
Will be interesting to unravel mysteries of evolution. But I don't want this to happen at the expense of a life of an innocent laboritory manipulated animal.