Quoted:
Fire pistons, especially the expensive ones, are not strictly bought for utilitarian purposes. Some people enjoy the craftsmanship and art of utilizing a fire piston.
Its like complaining about someone's $150 hand carved wood duck call... Just something people like.
I personally like to carry at least a couple of methods of starting fire. A couple of lighters and a striker/blast match style are my usual.
No complaining about a fire piston, or the fact that somebody might want one just to have it, but it just seems to me that there's a learning curve and one might not be able to get the thing sparking/igniting the char-cloth in cold and wet conditions, is all.
Also, they're not all that cheap and they do use o-rings to contain pressure and those can go bad over time, so they're not infallible.
Carring an Altoids tin of dryer lint smeared with Vaseline, a magnesium starter, or a ferro rod with a striker, along with a basic BIC lighter, might be more prudent in a stressful situation, is my thought.
Chris