Another perspective on the food is for people with diet restrictions. I'm a vegetarian and have some medical issues on top of that, so when I hear "food is provided" that doesn't really motivate me because I am going to assume I can't eat anything. Maybe I WILL be able to, but it's better if I eat first or at least bring a protein bar to get me through. And honestly, some of the smells of food are off-putting for me, especially when I'm not feeling tip-top.
So for ME, a free event with no food is vastly preferred to one that has even a nominal cost and food provided. I also won't have to worry about clueless but well-meaning people touching my project (or fabric in the store) with their greasy pizza-sauce fingers!
I think if I were you I WOULD talk to the owner and suggest she at least try a new format out and see what kind of results she gets. You're trying to help her business succeed and I think that's wonderful. Hopefully she'll get a nice group of regulars that forget stuff at home a lot (so they need to buy stuff in the shop)!