Personally, I don't believe in Bitcoin either, but one thing I was considering is that Bitcoin is usable as long as its value isn't 0 (though it might be incredibly difficult to use with fluctuations).
So the question is will it crash to 0? Seeing the price soar to 1,000 means that people in the future might always be willing to purchase it at some price, hoping that it will return to that level.
Though, as it stands I don't think speculation gives it credibility. People who believe that are creating the positive reinforcement cycle so common in economic bubbles.