Why is there free choice?

The rabbi’s explanation regarding the existence of human evil in the world is that without the possibility of evil, there is no choice, and therefore, in order to allow free choice, a person must be given the opportunity to choose evil.
Does the rabbi have a suggestion or explanation for why God wants us to have free choice and why He created it?
It is understood that for free choice to be possible, there must also be the possibility of choosing evil.
But why do we need free choice?