User blog comment:Admiral Sugar/Thoughts on Devil Fruits/@comment-53539-20140217110540

Where do you think Devil fruits originated from? Do you think they come from the Void Century? Why do you think that not being able to swim is the curse for eating one? Do you think they have anything to do with the devil? What secrets do you think Vegapunk knows about them? Do you think they grow on Trees? Why do you think they taste horrible?
 * The previous user died and the fruit was reborn... Oh wait.. This is a "what came first, the chicken or the egg?" question really.
 * I'm not going to bet money on it, but we've had nothing on DFs that isn't recent (last few centuries) history. Take note that its likely as more and more folks enter the grandline, DFs got spread across the world, and that most folks outside of the GL have never even seen a DF or know much about them... But it seems odd that the history we've seen in OP doesn't mention DFs in the distant past. Noland Montblanc is a typical example of what we're seeing, not one character in his story had a DF ability. I've always found this odd.
 * In context of storyline, dunno. But I see the logic in there being a weakness.  If there was no risk involved with DFs, they'd be too overpowered and there would be no justification in having members of a crew who don't have one like Zoro, Sanji, Nami, etc. Also, no weakeness weakens the super strong non-Df users like Shanks (who as far as we know still doesn't have a DF power) and puts less emphasis on why it was so important for Luffy to know how to swim before Shanks would take him on board his ship for a trip.  Whe thrown in the water in chapter 1, Luffy couldn't do a thing to save himself, so if Shanks didn't save Luffy we'd have no sense of the real danger that swims under the OP ocean. :-/
 * No, but due to the fact to get around the OP world you need to use the ocean for the most part due to its layout. Again due to the dangers of the sea, in the past I guess people were likely more superstitious which in the real world was a issue in itself.  People used to send out offerings to the sea gods and things like that and pray for safe passage.  These superstitions likely are still being used in the modern OP world.  Its much I guess how people still believe things like "Don't walk under a ladder" or "breaking a mirror is 7 years bad luck".  "Devil" also be used by the people of the OP more as a metaphor to describe the way the DF's work, since it must seem odd even to the people of their world that the only common thing all DFs have is they are "rejected by the sea" and due to the fact the sea is harsh... Is the ship hits a disaster, DF users are in dire trouble.
 * We shall see.
 * This has been answered in the series with "Smiley".
 * Guess to enforce the idea of strengthening their connection to the "sea devil". But also to make a point I guess on how different they are to other fruit of the world.

They are a simple idea to make superpowers in the OP world which are easily controllable. If you look at other stories, often powers can be a runaway affair. For example. What is the limits of magic? If there are no limits, how does anyone with no power survive and why hasn't the world been conquered/destroyed by those with the power. If there are too many limits to power, why learn it? If its not useful enough, it weakens characters with the power. Also, OP's DFs mean that characters with a particular power stand out more then others. :-/