1.) They don't move much (or at all really)
2.) They can provide good home defense
3.) They never expect anything from you
4.) They flourish off neglect
5.) They don't take up much space
6.) If the cactus becomes too much of a hassel to look after, you can kill or leave it behind without any moral qualms
7.) Child proof (mostly)
8.) Useful around the house (it's a great paper weight)
9.) They never talk back or hold contempt (can't remember things when you lack a brain and central nervous system)
10.) Generally won't make trouble with other items or organisms around the home
-
But you can't pet them.