In times past, both were used along the property border to deter trespassers. Their sharp points can stab, the spines on the foliage edges can tear and their thick, wide clustering growth can make the plants armor hard to avoid. They can be dangerous to work around, too, so larger ones work best as a single specimen. Instead, combine with landscape boulders if the bed needs a finishing touch. Smaller varieties however, can work well with other drought tolerant plants, creating a very low maintenance landscape. They're all salt tolerant and do well in beach side plantings.