When a rare animal is spotted or found, it is a good sign that while the species might not be thriving or particularly large, it is still here and that is always positive. Once the species has been spotted also, it gives us the chance to search more and potentially help keep the species alive if there is a way.
A rare whale will have unique genetics and characteristics that scientists can study. The find can help scientists study evolution. Perhaps there is another species. Perhaps scientists can study breeding and how to produce desirable characteristics in future generations of the animals. There are so many possibilities from finding a rare species of whale.
Considering the unfortunate fact that this whale is rare to begin with, finding a rare whale is a good sign for the species. It could mean that their are more of the whales and thus easier to come across. It could be a sign that conservation efforts are working for the species.
It is always a good thing when a rare animal is found, as it is a sign that a species may not already be extinct or on its way to being wiped out. It will better if we can find full pods of these whales, but as it stands we know there is at least one.