It seems that many people are still not proficient in nestjs. When showing test code, it seems that they do not know well when to use useValue, useClass, and useFactory, as stated in the official documentation. Also, the lecture video is not well organized. It was edited from a live broadcast and produced as a lecture video, but the lecture video itself is not organized and sometimes contains incorrect explanations. Of course, the incorrect parts are explained in subtitles or supplementary videos, but I think that is not good in itself. It felt like they were not proficient enough in the framework to film a paid lecture on nestjs.