That is the thing about self compassion.
My understanding of compassion is that it is more than trating yourself as a best friend -- that is a short-hand if you have diffculty generating loving-kindness for yourself.
Life does not always give you a choice. You are not always in control (though one should still keep their wits about them). A sense of agency can again, augment the false sense of self, no more different than self confidence or self esteem.
Self compassion is different. It is loving-kindness directed to oneseld whether one is doing great or doing bad, on top of the world or hiding in deep shame, heroically rising above or writhing in guilt, having a strong sense of agency or lacking it.
It is much more painful to recieve loving-kindness when you are wounded. Loving-kindness doesn't soothe away pain so much as bring it into greater attention and allow the pain to be felt, accepted, and change can take place. It is only then that there is a transformative effect.
It can be difficult to generate loving-kindness towards oneself if you've lived a lifetime of self-judgement and self-harm. You might have forgotten what it felt like.