This card makes it more viable to use non-"Madolche" monsters (that still benefit from their effect) in your Deck. It also returns "Madolche" monsters that are in your Graveyard and any Tributes and Xyz Summoned monsters.
When one of your "Madolche" monsters is destroyed and sent to the Graveyard,(as long as it's not chained to a monster destroyed by battle during the damage step) you can chain this card to their effect to return them to the Deck. You will also get to return one of your non-"Madolche" monsters without any effort.
If you use "Giant Rat" in a "Madolche" Deck, you can use this card's effect to return it to the Deck and use "Giant Rat's" effect again.
If you Tribute a "Madolche" monster to Summon "Madolche Puddingcess" you can use this card to return the monster you used as Tribute to the Deck and possibly emptying your Graveyard of monsters, giving Puddingcess a 1600 total ATK boost. This technique works even better if you have "Madolche Ticket" on the field, as it would allow you to Summon any other Madolche monster from your Deck.
If you use this card with "Madolche Chateau" (play it after you play "Lesson" or chain lesson to "Chateau") you could activate "Ticket's" effect to Special Summon a "Madolche" from your Main Deck, and Puddingcess will be at 3100 ATK.