A bad call for many reasons..
1. Ok, so saving them may be eating up conservation cash. But if they are left to become extinct, then this undermines the conservation effort in general. So people may become dis-illusioned with it ("can't even save the Panda") and so in the long run there will be less conservation cash to go around.
2. Letting a species become extinct is a one-way choice. If it turns out to be wrong in the future, there is no going back.
3. Panda's may not be that great at storing fat to hibernate, but as they eat low-calorie foodstuff and manage to survive, they may have adaptations that are unique and identifiable in terms of efficient energy utilisation. If so, understanding these may be a valuable resource for us humans.