Christkindlmarkt sounds like a nice idea and would help get people in the Christmas spirit.
While living in Germany, I do not remember seeing any vendors who were competing with normal businesses such as clothing stores, grocery stores, banks, drug stores, sporting goods, hair salons, clock, camera, bakery or jewelry stores. They did have curry wurst, pretzels, some cheese and wurst, special Christmas cookies, cakes and candy, carved Christmas Nativity scenes and figures, special trinkets, etc., and of course my favorite, gluhwein.
It appeared that while they were at the Christkindlmarkt, they did some of their normal Christmas shopping if there were any real stores to shop in.
I admit, if your store sells alcohol, pretzels, wood carvings or Nativity scenes, the market may cut into your business.
There were always special times for choirs or groups singing Christmas carols. My wife sang in a German-American choir for three years, shivering in the cold weather, but had fun. I just watched and listened, and drank hot gluhwein.