CMIIW, those protective charms works like silica gel. Instead of giving good luck, they absorb the bad luck instead. That's why it's a common thing to replace them every year when they have became too saturated.
Actually, she's squeezing it so tightly in the third panel that she crushed it into powder.
Psh....Thank you...A good luck charm?I bought it from a shrine with a very good reputation.squishji~iinvery much!May... I ask you... to scrap me?With this, your bad luck will go flying away!The charm...Admiral....Wait, don't be so hasty!