I guess being self compassionate when you are doing great does not bring a big benefit, but neither does it hurt. However as the article mentions, it's hard to have self esteem when you are not doing that great.
As a PhD student I have this imposter syndrome feeling whenever I hit a wall. Being self compassionate and realising that almost every PhD student hits one or more walls during their PhD has helped me to cope with this.
Loving-kindness while one is doing helps one see through complacency and turning into an asshole. It also naturally start bridging into loving-kindnes for others.
As a PhD student I have this imposter syndrome feeling whenever I hit a wall. Being self compassionate and realising that almost every PhD student hits one or more walls during their PhD has helped me to cope with this.