If the word "clone" makes you think of an army of blank-eyed soldiers bent on destroying the human race, Dr. Hydro recommends you stay away from the sci-fi for a while. Maybe try a nice romantic comedy. Because when it comes to plants, clones are your friends. They are simply a new plant grown from a cutting taken from an existing plant. That is, you can cut off a short stem with a leaf from a full-grown plant and let the cutting take root and grow to maturity.
A primary benefit to creating clones is that new seedlings propagated this way will have the identical characteristics as the original plant--size, shape, color, flavor, etc. On the other hand, seeds will have the traits of the two plants involved in its production: the female plant that bore the seed and the male that pollinated it.
Clones also give growers a head start over seeds because they already have leaves and can begin photosynthesizing and growing as soon as they take root. Cloning is the quickest way to increase your supply of plants.