If I understand this correctly, it looks like the only way to get 2nd affection gifts is by forging. The forging conversation rate is, essentially 1/20. That is, you can get 20 girls to full normal affection with the amount it takes to get 1 girl to full second affection. Maybe the long-time players have all their girls at full affection but for now, the 20 flower gems for getting a girl to full affection seem far more useful than burning gifts in a forge in an attempt to get a girl to full second affection.

Are the extra stats on the one girl really worth the loss of 18 flower gems?

Am I mistaken?