Pokémon Mystery Dungeon
>In Pokémon Mystery Dungeon: Explorers of Time, Darkness, and Sky, as well as previously mentioned effects, Normalize turns the standard attack into a Normal-type move. It also makes throwing items deal Normal-type damage. This does not apply to fixed damage items (Geo Pebble, Gravelerock, Unown Stones, or Rare Fossil).
So you receive STAB from throwing items and from most of your moves, meaning you deal more damage. That's the only advantage to Normalise, but you need to be careful with Ghost types.