Sweet potatoes and white potatoes, to me, are two totally separated foods. Not interchangeable. But that is me. Potatoes are a starch. Sweet potatoes a great alternative to dessert; just crumble a little raw brown sugar and butter on it. But that's me.
They have a few more calories per hundred grams - 87 as opposed to 76, so shoyuld be treated with caution on a calorie-controlled diet. If you are not on a diet, they make delicious crisps (US chips) cooked in the oven, lightly sprayed with oil and salted.