This card can be an effective defense monster against your opponent, in case he has another monster to attack you. In addition, you will be able to protect it for a potential Synchro Summon in your next turn.
The lore of this card was mistranslated. The DEF boost only last until the End Phase, it is not permanent.
Since it's a Quick Effect that alters DEF, it can also be used during the Damage Step, making it a good card to set as well.