That seems fine to me. I'm sure you unlock it as a fighter towards the end of the game.
I phrased it wrong. What I tried to say is that you can only use this pokemon to fly, swim and ride. The other pokemons don't have any use other than battling. This legendary going to your team to battle is given.
And the fact that this pokemon is classified as legendary but everybody is riding one on the trailer is just mind-boggling
We reap what we sow