Zantedeschia, or the arum lily as it is known in South Africa is neither a lily nor an arum. If you use them as cut flowers just remember that beneath the outer veneer of beauty they are poisonous, because of the presence of calcium oxalate.
My one field guide says that it does have medicinal uses. The leaves are warmed as a poultice for sores and boils and warmed leaves are placed on the forehead for headaches. Not being into traditional medicines, I have never tried it and don't recommend that anyone does.