u/Furby-saurus

Hi I'm a Slowking player and I like looking at other Slowking lists to get ideas. Recently I've been noticing everyone seems to be playing Lillie's Clefairy instead of Regigigas for the Dragapult matchup. Can someone explain why Clefairy is better? I'm nervous to put another 2 prizer on my bench in addition to the Latias, Mega Kangaskhan and sometimes Fezandipiti. And Regigigas is easier to search for because of Pokepad. What am I missing that makes Clefairy so good?