Roller shutters installed outside your home can help protect windows from damage during heavy storms and high winds, and will also provide maximum light and sound blockage inside the home. However, you can also use interior roller shutters over the windows, and even in other locations around the house, for light blockage, or to create separation between rooms and items you're storing. Note what is meant by this, along with some ideas and inspiration for using interior roller shutters.
Over patio door walls
A sliding glass door or folding glass doors that take up most of a wall in the home can be very difficult to cover with a window treatment. Curtains that are large enough to span this space can be cumbersome and bulky, and may not fold back far enough to keep the entire door unobstructed. Vertical blinds can be noisy and look somewhat industrial.
However, roller shutters above those doors can mean a fully unobstructed view, without the window treatments getting in the way of the doors themselves. These shutters can also offer more flexibility over how much light you get through those doors, as you can partially close the shutters to offer some shade, or close them completely when needed.
If a room is very small and crowded, a standard door may hit furniture or get in the way of foot traffic. Roller shutters can be a good option, as they don't need any clearance to open, except for their housing unit above the doorframe.
Roller shutters can also be a good choice for overly large doorways; if you've expanded a doorframe to accommodate a wheelchair, or just to keep a space open and airy, doors that fit that entryway can be large and cumbersome. Roller shutters can then be a good solution for any oddly-sized doorway, whether it's very big or very small.
Roller shutters can hide anything you want to keep stored and out of sight. For example, you might have a tall set of shelves built in the kitchen to store your small appliances, and roller shutters over those shelves can keep them hidden away. You might also have a sunroom or addition that you use for storage rather than relaxing. Adding roller shutters to the entryway of this area can block the view of those items you're storing, without having to add cumbersome and large doors or trying to hide those items with bulky curtains or room dividers.