To floor or not to floor in a truck topper type coop

[WillowHavenFarm]

We are considering building a coop with a truck topper as the roof. I have been perusing photos, of this type of coop, on-line and have noticed that some do not have floors in them. Curious on the thoughts on whether a floor is necessary or not. We live in Michigan so our winters are rather cold and we don't intend to move the coop around much. If not building a floor is okay we would bury hardware cloth around the coop to help keep predators at bay. TIA for sharing your thoughts and experience.