I feel some of the answers here are too categorical. They fail to distinguish between the chocolate format and the blend. There is no one-to-one relationship between the format (e.g., chip/wafer/block) and the blend (ingredients, esp. the quantity and type of fat).
Couverture-quality chocolate, used for confections and ganaches, will typically only use cocoa butter as the fat. In particular, premium chocolate for coating ("couverture" = blanket, covering, coating) relies on cocoa butter for tempering. Such chocolate can be provided in any format, including chips.
Chocolate chips specifically intended for baking will have less cocoa butter than couverture, or even no cocoa butter, substituting other fats. This isn't necessarily a quality issue. Couverture-quality chips melt more easily and with greater fluidity than you may want for baking; the melting chocolate may spread out too much in the batter during baking. Chips specifically for baking use a different fat blend so that they keep their integrity better during baking. Of course, some manufacturers may use an inferior blend to keep costs low, sacrificing quality. But even premium manufacturers often use different blends for baking chips vs. chocolate intended for confections.
Speaking for myself, I often use some couverture-quality chips or wafers when I bake cookies or blondies. I don't care that they spread more in the batter; I kind of like that, in fact! That said, I do also keep baking chips in stock, and I tend to mix them and couverture chips and wafers when I bake. This is partly to control expense, but also there are some baking chips I do like a lot. I much prefer Ghirardelli and Guittard baking chips to the standard store brands (Tollhouse, Hershey, Bakers). Guittard in particular is a US chocolate manufacturer that is very well known for their couverture-quality chocolate for confections (sold in wafers and blocks); but they also produce chips specifically for baking.