I actually have done that, but Qbit's built-in search doesn't have the same search filtering options. For instance, I can't sort torrents by upload date on the Qbit web-ui (this is the most important missing feature, imo), or set it to only search certain indexers and not others, and it has no category related options. It has the essentials, but the Jackett interface is just cleaner and more feature rich in my opinion. That's why I stopped using the Qbit search engine in favor of Jackett.