I think antimatter is more properly viewed just as hydrogen or batteries should be viewed. That is as an energy storage medium. You have to make the hydrogen from some other energy source and you have to charge your batteries from something. Just so, you have to have an energy source to make antimatter.
That having been said, it is the densest energy storage medium concievable and would be invaluable as a propellant in space. Just as Annodomini2 suggested.