Better to prepare for a counter attack where you won’t have to deal with fighters in the battle and coastal bombardments. So no defending the atlantic wall in this version of the game.
I think this take is mostly accurate but sometimes Allies have so many transports and (UK) fighters that they might be able to hold Normandy (especially in cases when the bulk of the Luftwaffe is far away). In cases like that, it might behoove Germany/Italy (let’s say they are defending Germany, West Germany, and France from a big Allied fleet) to move the France stack to Normandy. If the USA force is relatively small and the UK force is not enough to take Normandy, a 1-2 attack would be costly and risky. Landing in Holland instead is not always an option, since it’s adjacent to Normandy and W Germany and within tank/mech range of Germany).
In circumstances like that I’ve had success stacking Normandy with a combined German/Italian stack.