Cacti are often forgotten plants – intentionally and otherwise. That doesn’t mean that they are lesser carbon-based bits; they have their good points too.
1.) In the instance of a drought, cacti are VERY considerate.
2.) Cacti have thick skin and protect themselves from uncaring users/predators. This is a good life skill and a solid example that many folks would benefit from following.
3.) Cacti pretty much thrive on neglect, unless you are in Antarctica. (If you are in Antarctica, pretty much nothing is thriving.)
4.) Due to GT3, people who are generally unable to keep a plant alive can practice on a cacti, potentially building their eco-confidence.
5.) Some cacti (e.g. prickly pear) are edible. The edible ones tend to be fantastically rich in nutrients.