I agree that it can be valid to craft a dispenser with an enchanted bow, but I strongly believe that the recipe book's auto-fill should scan the inventory for any usable non-enchanted bow and use that before trying to use an enchanted bow.
I just accidentally lost my best bow because the enchanted bow always seems to be picked first (which may be because it's on the hotbar).
For what it's worth, I would like to see this changed, this current behaviour makes the trident much less useful than the other weapons available.