You can use this effect to stop effects that cards like "Loki, Lord of the Aesir" use to resurrect itself, since their effect specifically say destroy, something this effect does not do.
This card sends all cards on the field and in both players' hands to the Graveyard, so try to use this card's effect when you have "Sangan" on your side of the field or when you have "Night Assailant" in your hand. This way, you can get a monster to your hand just in case something goes awry. A really good card to get in this case is "Yata-Garasu", because it can completely Lockdown your opponent.
Use this card with "Cold Wave" so you can wipe the hand and field without worrying about your opponent countering its effect. Note: you must have "Umi" already on the field to work.