1. What does it mean?
A variation on 가성비 that replaces the performance-focused 성 with 심 (心, 'heart' or 'mind'). It shifts the question from 'how much does it do?' to 'how happy or satisfied does having it make me?'
2. The nuance
This describes subjective satisfaction, not a universal quality score. A choice with high 가심비 for one person may seem pointless to someone else. It is not a claim that emotional appeal makes any price affordable.
3. Examples
“조금 비싸지만 매일 쓰면서 기분이 좋아서 가심비는 높아.”
It's a little expensive, but using it every day makes me happy, so it feels worth it to me.
“나는 디자인이 마음에 드는 컵을 고를 때 가심비를 봐.”
When choosing a mug with a design I love, I think about how much enjoyment it will give me.
Sources
National Institute of Korean Language
Korea Policy Briefing: language and culture
References support the meaning and usage. Example sentences are written for NoCapWiki.