Yes, aluminum coils can be used for decoration in the garden. They are lightweight, durable, and resistant to corrosion, making them suitable for outdoor use. You can form them into various shapes or use them to create unique garden structures such as trellises, sculptures, or even as part of a fence. Their metallic finish can add a modern or industrial touch to your garden's aesthetic, and they can be painted or left in their natural state to blend with different garden themes.