The first Jurassic Park quote applies here, a few have used a variation of that idea of doing something just because you can. The other quote follows it, "Dinosaurs and man, two species separated by 65 million years of evolution have just been suddenly thrown back into the mix together. How can we possibly have the slightest idea what to expect?"

These aren't dinosaurs and are a lot closer to us in the timeline, but definitely reintroducing them in a large scale would have some effect to the environment they're put in. Perhaps we only make a few...seems kind of pointless though to bring back a species but keep them at extinction levels. And can they even survive as they were in a warming planet? We might not even be able to, and we're younger and current.