A live performance is a very unique experience.  Each performance helps a pianist get used to playing in front of other people, learn how to stay focused and relaxed, and learn how much preparation (and what kind of preparation) is needed in order to play well.  In this day of perfectly mastered recordings, I think we come to expect a higher level of perfection than is really possible.  The 'perfect' performance is an illusive beast.  It is an area about which we all continually learn more.  Playing frequently for others helps us to develop a healthier perspective about the nature of live performance.  (Sometimes we play beautifully, other times...well...not so much.)  We also become pianists who are more comfortable sharing our music with others.

No event is ever required for my students, but I will definitely encourage students to participate. There is no quicker way to improve one's skills.  Each individual can decide which activities would be the most enjoyable and/or beneficial.