The games are supposed to resemble the first games, and Game Freak goes all out sometimes for Nostalgia in their games, like how in Hg/Ss you can get an item that changes the game's music to the original Gold/Silver sound effects. Also, Game Freak isn't concerned with how useless some moves or Pokémon are, and generality don't care about how viable things are so long as it isn't absolutely broken. They care more about the Pokémon's biology and dex entries more than most other things. :P