Let’s say you have a newer type of art, whether it’s a unique painting or piece of jewelry, people passing by your booth have never seen it before. They leave without buying from you and they are very interested in your product. Now, they are at home figuring out where your piece would go or when they would wear it. On top of that, they are now researching artists like you to see who else makes what they want.
They are researching prices, quality, shipping times, etc. If you make an amazing seashell necklace and sell it for $150. A consumer will go online and see if they can find something similar to what you sell, but less expensive.
This is why getting their email is so important, so you can tell them what makes your product unique and worth every penny of that $150. Whether it’s because you handmake each one or they are all from the same local beach to which the consumer may have an emotional attachment. Or maybe you flew to Fiji because you can only find a specific shell there.
Without telling them this info how would they know? The traffic levels of many art festivals make it impossible to tell everyone all the details that you’d like.