No, it is not a good idea for you take the welding goggles as the sunglasses because of the different inner materials. The welding goggles just protect your eyes from the strong lights from the electric sparks. However the sunglasses will protect your eyes from the uv rays and other bad lights. Their role is different. So you should not mix them.
Ok, it seems that you are quite interested in those welding goggles . So, anyway, as you can see, those goggles could protect your eyes against those welding flashes, which are quite dazzling. And it is true that those welding goggles could prevent your eyes from hurting by the sunshine. As sunshine is far less superior to flashes. However, it would not be a wise choice for you to wear those goggles in public, which could make you look like a nerd and freak.