Well the allies don’t want hitler’s main force to meet head on with the allies and there would already be many casualties and they don’t want more. Plus if they fail to land on the beach, Hitler could do something to America or Russia. Sure the prime minister Churchill could land in Germany but the roses is hard. Hitler knew an attack was coming but don’t know where, witht he help of a few spies, they convined Hitler that the attacks was coming at Calais. So alot of troops were stationed there but actuall it was in Normandy. It was mainly to prevent the loss of troops and to have a higher probability of suucsefully capturing the beach.
