It is good to experience the libraries that are widely used for handling libraries such as Firebase, SnapKit, Alamofire, and Kingfisher. However, since the lecture materials are old, you have to fix errors due to Swift version compatibility here and there, and you also have to fix version compatibility errors in the library. And there are many bugs that stand out when you finish the lecture. However, since there are not many iOS lecture materials, it is good for studying at this level for free.