The swan plant is a food source for the caterpillar of the Monarch butterfly and other butterflies of the Danaus species
It is also commercially used for stuffing pillows and comforters ( from the cotton that the seed pods produce)   

Gomphocarpus physocarpus is widely used in traditional medicine in South Africa. The roots are used to treat stomach ache. Leaves are dried and ground into a powder that is taken as snuff for headaches. The milky latex is used to treat warts.  Applied externally, it is used to treat sores, boils and swellings on the neck