All agaves are not equal
Agaves are a group of xerophytic plants, able to withstand drought and in many cases, strong sun. Perfect for Perth summers. There are many species and some are sharp and spiky at the leaf tip, so consideration needs to be given to their placement. Many make excellent potted specimens.
In my wanders with the dogs, I have noticed that people are planting agaves on their verges to stop people parking on them. Unfortunately, some of the agaves are going to be quite a problem in the long run as they form strong thickets with tough roots that are very hard to dig out. In one case, the young plants are hidden by tall grass, making them a bit hard to see. Bear tried to walk right into one which isn’t great with those eye level spikes.
The Agave americana or century plant has nasty sharp points on each leaf, making them dangerous in a confined space. If the space isn’t confined now, it will become that way in a few years when the parent plant has sent out many tough little babies to colonise the area. It probably gets planted sometimes as one of those, “Well, I don’t care, I’m selling the house” plants that people use to sell their houses. It easily grows from seeds, which can germinate on the plant, then disperse from the metres tall flower spike. It also produces many side shoots that can come up a metre away. The plants form close clumps and the stems stay short, completely covering areas with their leaves and pups.
The far less intrusive and softer Agave attenuata is a popular landscaping plant. This species is sometimes known as swan neck agave as it grows a tall stem where the old leaves fall off. The leaf is over all softer and more suited to gardens.