When used with water, it tastes very bland (such as in sauces or stews.) When used in frying, it tastes more potatoe-y. More of the malanga taste comes through in baked goods.
Can be used as a thickener. Can also be used as a coating for fried foods (some say very good on chicken), and for dredging.
Malanga flour is reputedly good for people with food allergies, as the starch molecules are very small and easily digested. Companies that make food for people with food allergies use it for everything from bagels to fettuccine.