Cleffa is not a power house in the Video Game world at all. With that being said, it can still find use it Little Cups. Cleffa can use it's hidden ability of Friend Guard to reduce damage done to allies in a double (or triple) battle by 25%. This is pretty drastic when it comes to baby Pokémon fight baby Pokémon. Cleffa also has a pretty vast moveset coming from Shadow Ball to Fire Blast and from Magical Leaf to Dream Eater. I personally think Metronome is a must have staple when running this family.