> To observe and study them, for one. Also, to see if we can (and learn how to and how not).

The thing is that they are not actually bringing a species back. Rather, they are creating something that superficially resembles an extinct species based on an equally superficial set of selection criteria. Genetically speaking their "quagga" is still going to be much, much closer to the population of zebras from which it was bred, compared to actual quaggas. So whatever we learn from those "quaggas" is unlikely to be transferable to the historical quagga