Well, don't pet games featuring hard-to-pet animals make more sense than common ones?
Why play common pet games when you can simply go out and buy a real thing.
A talking hamster, a dog that learns 5 tricks in 10 minutes, why do I bother with those.
On the other hand even if developers do some random crap in this game, how many people are gonna say "Hey the game is crap, my pet dolphin doesn't behave like the one in the game"