Why do Chalets have flat roofs?

My photo was taken at St Ives Bay in Cornwall

This photo shows the large amount of “safe” areas the children had to play in. The chalets were built with doors facing each other in a big square so that you could keep an eye on the children easily. I took this photo to show how well all the children in our area were getting on with each other.

This photo was taken by Mrs Jackie Dale from Scotch Orchard Primary School