Actually, chaya is a succulent in the euphorbia family, so it does not take a lot of water, though it is tolerant of brief periods of flooding once it is established. In my experience, it thrives on neglect, which is the kind of plant I like the most.
In fact, cuttings need to be cured for three or four days prior to planting, to keep them from rotting, and it is best treated more or less as you would treat a cactus, until it has started putting out leaves. And chaya handles drought extremely well, making it valuable in arid areas, including sub-Saharan Africa and the Middle East.
And yes, it has to be cooked prior to being eaten, but for smoothies you could blanch the young leaves for a minute in boiling water and then toss them in your smoothies with no issues.
Older, mature leaves need to be cooked or longer, say 10 to 20 minutes, depending on what you are using them for, but their nutritional profile makes it more than worthwhile. And the water you cook them in can be drunk as a tea, safely, as boiling deactivates the toxins in the leaves, and leaves behind a multitude of nutrients. Or you can use it for soup, and either way, it is very tasty.
Chaya is considered highly medicinal in Mexico and Central America, and is used for everything from regulating blood sugar to detoxifying the liver and kidneys to strengthening the heart and lungs.
And it makes for a gorgeous specimen plant, with the large deep green maple-shaped leaves, and the masses of small white flowers standing straight up from the top of the plant. It is a butterfly magnet, but it is not invasive, as it rarely if ever sets viable seeds. It is nearly always propagated by cuttings.