We will not conceal them from their children, but tell to the generation to come the praises of the Lord, and His strength and His wondrous works that He has done. Parables are very useful because they engage the listeners attention and convey instruction in a manner that is fairly easy to understand. When Christ chose to use parables to speak to the multitudes He picked a form of communication that was well fitted to a large audience. If Christ had simply stated truths as propositional statements, it would have been likely that much of what He said would not have been understood, but parables made these truths available to everyone who could hear. Another reason why Christ adopted the mode of parables was because it was a common method of teaching in the Jewish communities.
Parables are a way of teaching that can allow truths to enter the mind tactfully.
They also can conceal the true meaning to those who will not listen to truth. Other times a parable can only be understood by considering the context, or reviewing the circumstances under which it was spoken. However, most of the parables of Jesus are very easy to understand if they are received by a willing mind and heart. The parables of Jesus were very useful teaching tools. Simply compiling a short list will bring many truths to mind for many of you.