As you may have read, I have just recently participated in an art show, but prior to that I have done a great number of demonstration in various locations, mostly for educational purposes. The educational side will not be part of this post. Here we talk about why it is important to show people you are not a factory pounding out soulless items for pennies on the dollar. You are a hard worker, you breathe, you most certainly sweat, and you, hopefully only occasionally, bleed to get the job done.
There is nothing quite like watching somebody shape something from nothing, to start with the formless and end with the complete. Further still, the sound and smell makes people feel like they are truly experiencing something genuine. This isn't some video being streamed, not some podcast or TV show, and it is most certainly not some game with big blocks and pick axes (you know which one I am talking about. If you don't, just ask if a kid knows what a pick axe is and how ingots are made, you'll get an earful), this is honest work being done right before their eyes. They may not remember your name but they will remember your actions and they will remember the time they saw someone shape metal to his (or her, this is a modern world after all) will.
Demonstrations, especially while at a craft fair, give you the opportunity to truly show people the work and skill that go into making something. It gives the individual a true appreciation for your dedication, the practice, the passion. It gives you the opportunity to actually explain what you are doing and how it differs from what they see in regular stores. It proves that your goods are hand made. And, frankly, it is just damn interesting. It does not matter if you smith, carve, spin, sew, mold, whatever... If you take the time to physically do the job rather than just talk about it people will listen, people will watch, and even if they don't buy what you are selling at least they walk away knowing you are the real deal, you are the face of your work.
So go out there and be proud of your failures because they lead to your successes. Be proud of your struggles because it lets people know your not the faceless factory shaping the same item every time, every day.
Also, be proud of the fact that you have to tell kids you can't craft a set of armor in minutes, scare them by saying your fuel (coal/charcoal = mostly carbon) is basically baby diamonds, and no, blacksmiths don't make gold swords (again, if you don't know what I am talking about you should spend more time around young people - they are the future, like it or not).