I would die just to see Sora wear a tube of lipstick! Or maybe Riku?Maybe when Kairi puts it on, she senses a power within...something beyond the special attributes it bestows. When she focuses on it Tink appears!
It should be a long quest throughout the worlds rather than bought. Then finally it appears in a chest.
Also Sora can equip it himself as well because he’s like the series’ Jack of all trades type of character.