Obviously, your tame dragon will not be quite as strong as the most formidable dragons in the game, because then you would be playing an entirely different game in which your dragon just does things and you cheer him on. But he can unleash his breath weapon, take to the skies, dart quickly from place to place, and carry both you and a friend through the skies. All of those tricks have long cooldowns, but you should be happy the dragon is doing all of these things for you instead of to you. Be thankful for what you get.
Source: Official Site