'More value'... Uhm, you're joking, right? Know Thyself is Priceless, and that - that very thing - is the Lesson Argent Mirror holds for us. Ignore the other bonuses, the dice, the reroll. Knowing who you are, and why you do what you do, means that others lose leverage over you. That Ling Qi can center herself, even when her alignments push her in directions she doesn't really want, and understand the truth behind her actions, behind all the little lies we tell ourselves to make us feel better... without judging herself for doing those things.
It'll help us not do the sort of thing that Gu Xiulan did these last few months - how sharply she changed, from the girl who said that 'appearances are power' to one who is solely worried about appearance because she is afraid of what her mother would say? - and keep ourselves largely as we are, even as we delve ever more deeply into the moon-dappled shadows and haunting melodies.
"If you know your enemy, you will win half of your battles. If you know yourself, you will win half of your battles. If you know yourself, and your enemy, you will not be defeated."
-Paraphrased.
The Argent Mirror Domain is a perfect opportunity to ensure that we know who Ling Qi is, and that we continue to know who she is, IC and OOC.
As for lowest tier? That the lesson is learned and understood matters far more than when you learned it, or how hard it was to learn.