Well, I think it is actually related, gerry, at least to me. If your practice strategies are sound, there is not really a "point" in "memorizing", it just happens. The point of learning the piece is to know the piece, and if you really know the piece (inside and out), it will be remembered. However, people often approach pieces as though there are two separate stages, learned vs. memorized. And this kind of memory, even under normal circumstances, is unreliable and may seem pointless. However, if a person's practice strategies are sound, memorization will naturally happen as a person gets to know a piece.
I don't think a person needs to wonder what is the point of knowing a piece. However, a good question may be, how do we really get to know a piece ?
As an interesting metaphor, wouldn't it be funny if instead of people asking if you know how to ride a bike, they asked "have you memorized how to ride a bike ?" We don't really 'memorize' how to ride a bike, we learn it to the point of knowing how to ride a bike (and because we know, we never forget). Music can be a similar thing.