You can ruin your opponent's attempts at Synchro Summoning monsters and then destroy the Synchro Material monsters on your turn.
In addition to that, after this card is used you can possibly use it on one of your own monsters to Synchro Summon a more favorable Synchro Monster.
One possible way of using this card is to power up your "Junk Warrior". By reducing the level of high ATK level 3 and 4 monsters, such as "Gene-Warped Warwolf", "Junk Warrior" can get a very high attack.
This card can be used to help you Xyz Summon a specific monster if your Levels do not match with your Xyz Monster's Rank; alternatively, it can be used if you notice monsters on your opponent's field of the same Level, to disrupt their Xyz Summon.
This is especially useful against an opponent using "Rescue Rabbit". They lose the monsters at the end of the turn if they do not use them.
The lowest a non-Xyz Monster's Level can be is Level 1. This card can be used to change Level 2 and 3 monsters into Level 1s for a Xyz Summon of a Rank 1 Monster.
Xyz Summoning "Baby Tiragon" can allow you to use its effect on another monster affected by this card in order to allow it to attack directly.
Combining this card with "Pain Painter" in a Zombie Deck can make any 2 Zombies Level 2 for the remainder of the turn. Using this after will make "Pain Painter" and those two Zombies into Level 1 for Xyz Summoning "Baby Tiragon".
If another monster is used instead for the Xyz Summon, one of the reduced Zombies can have ther ability to attack Directly due to the effect of "Baby Tiragon".
Combining "Pain Painter" with "Baby Tiragon" is a highly efficient alternative to "Opti-Camouflage Armor" in a "Wight"-based Deck.