Window shutters and security shutters, while similar in a lot of ways, serve completely different functions. A typical window shutter which may be used in a second floor window serves the function of providing shade and privacy, while a security shutter is more typically found in doorways, in both commercial and residential properties, providing an additional layer of security behind or in front of the layer of glass.
For retail businesses having security shutters is all important. Implemented typically during periods of the day when nobody is present in the shop, they ensure that nobody can get through to the products in the premises, meaning that the worst damage a business will suffer from an attempt is a bit of broken glass. Due to the slotted nature of security shutters, they still allow people to see through the shop window to the products, meaning that the ability to advertise them is preserved.