Meitri's lost a number of Ribbon lamps...not a good thing during Asmodae's Festival of Light. Without the lights to guide Lady Lumiel's wisdom, how will she know where to channel Aether? Even if you don't believe the Lady Lumiel angle, the Festival itself is a big deal. And Meitri's already in trouble for pranking his commander. You got the stolen Ribbons back from the Gumigumis, and a relieved Meitri gave you a reward.