ShiroKuro So that's where the question is. Why perform?
The best reason I can come up with is if you can answer yes to the question of will your performance provide pleasure to the person hearing it (and if you have any interest in pleasing other people, which not everyone does). Thus it's the performer's own self assessment of their playing, and of the listener's expectations, that determines whether to perform or not.
Some people express belief in a "need" or "duty" to perform, but I'm not one of them. I play for myself. I can read a book or watch a movie for my own personal pleasure. Same with piano. At the same time, if someone want to perform, go for it! It's a big tent. There's room for both approaches.