Fairy lights are a string of lights typically used year-round, rather than only during Christmas. People desire them because they are thinner and less bulky, so are thinner to store than Christmas lights, they are LED which means they consume less energy, and their cord is usually transparent, which means that when they are lit up you actually only see the lights.
Fairy lights are a very small string of LED lights that are like a new version of Christmas lights. The lights are wired into the string so they can be hung in most indoor rooms and will emit enough light. They make great great gifts during holidays. The lights are a nice warm temperature and last longer than normal lights.