4) Some bettas love them because they are soft and smooshy and every betta deserves to have a soft and smooshy chair to rest on.
5) This is not really a reason, but a warning: These are gateway plants. You buy one, and the next thing you know you buy a few more. Then you realize you can keep them alive and the next thing you know you are buying every living thing that is green. When you go into a petstore, once you are done looking at what bettas they have, you look at what plants they have. And unlike bettas, you can add as many as you want to a tank. You notice a tiny, cute little crested java fern that looks like an angry baby version of your big java fern. That lucky bamboo has such a cute little curl to it's stem and would look perfect sticking out of "instert name here"'s tank! The list goes on...