Jesus always used stories to teach. I guess, back then, that was fairly uncommon because the disciples ask him about it. I wonder if they were like, man, this guy doesn't know how to teach, let's tell him how, or if they were like, this is so stinking incredible, let's ask him why he does it.
Whatever the case, Jesus says he does it to make his message more inaccessible. That's an interesting thought. I wonder if sometimes my stories make my message inaccessible. I hope that they create a relational point so that the hearer has a greater understanding of me and through illustration a greater understanding of God's truth. This is really a tough passage for me to wrap my puny brain around. JM