I would say that there are better things to eat than potatoes, but there are worse things too. They're cheap calories, so if you're poor, then sure, potatoes can be a useful thing to have as the cornerstone of your diet. They're better than wheat, for example, since they don't have gluten.
If you have to eat potatoes, some methods of cooking are better than others. Frying and baking are quite bad, as they chemically create toxins in the potatoes. But eating potatoes raw isn't so good either, as potatoes contain alkaloids that can cause harm if consumed consistently. They build up in the body. If you want to eat potatoes, I'd steam them, or, as was mentioned, boil them in soups or stews.
Other tubers you can eat raw more easily, without having to worry about alkaloids so much. Sweet potatoes are like this, and Jerusalem artichokes are great raw. If you can gain access to these tubers, they can be a calorie-rich dietary cornerstone that can be eaten raw.
