There are a couple of reasons. The first reason is I have a very temperamental Pleco. He rearranges the tank differently every single day, digging up plants, moving gravel into piles from one end for a while then back to where they started, and wants everything floating on top of the water. I’m sure it’s because he is in the small tank And he is way too large to be in the tank. Since I rescued him and the guppies from starvation and ultimately being flushed down the toilet, he has doubled in size so I understand his frustration, and have committed to providing him a larger tank soon, but I am retired and no longer can go spend hundreds of dollars anytime I want but I am getting a 100 gallon tank soon. I need the plants to live and do their job so I thought I’d try the terrestrial plants. The second reason is the roots growing inside the tank looked appealing to my aesthetic taste And roots floating around will offer some protections for the guppy babies. my husband who is a fisherman but not too up to date on keeping fish wanted to help with our snail problem and brought home three Bali sharks, two kuhli loaches, and two Cory dories. I know! So I am in dire need of a big tank and plants that my Pleco won’t beat up. And because I have the big fish in the 20 gallon, I vacuum the gravel faithfully ever six days and replenish the water, treated with dechloinater and ever other week, I do a 75% water change. He is watching me now and wants me to feed him pellets or worms or shrimp. If I don’t, he will try and get my attention.