The purpose of speech and dance is to express oneself. We get irritated when they 'show-off' their big vocabulary. Dance is no different. In the 'real' world, you learn a 90 minute show in 3 weeks. In competitions, you spend a year rehearsing a 3 minute dance.
Competition exists in any career.
Nonetheless, artificially created competition is unnecessary. It forces the dancer to focus on the opposition rather than themselves. This is true. Any performance experience is a good one. However, experience can be achieved in a performance where winning is not involved.