Gotu kola likes damp places and will grow as a ground cover where it is humid and gets regular water in shade and in sun. It creeps by rhizomes along the ground and roots shallowly. It propagates by cuttings. I don't know about it being semi-aquatic. As far as I know it does not grow in water like watercress.
Gotu Kola is bitter if you eat it. It is a medicinal plant and many of them are. The most common use of gotu kola that I know of is as a poultice for minor wounds and skin ulcers. It also has rejuvenating properties that is supposed to help with things like arthritis and aging. The latter part, I don't know about, I think genetics and activity plays a large part in that as well.
https://herbsarespecial.com.au/plant-in ... gotu-kola/
Happy gardening in Hawaii. Gardens are where people grow.