Why StatefulSets were barely mentioned in the course?

moebius5

Hello!

I've completed LFS258 course and now I'm preparing for the CKA exam, and by revisiting the course material I realized there is almost no useful information about how to implement the 'StatefulSets', I consider that entity to be a more complex object and should say as future Kubernetes administrators we have to "understand" the entity (create, modify, etc.) as we do using 'Deployments' or 'DaemonSets'. I've also bought LFD259 (Kubernetes for Developers) course in a bundle and I looked through the syllabus and didn't find any topic related to 'StatefulSets'. I haven't tried CKA or CKAD exams yet, but what if there would contain questions related to the matter?
Having completed the course I can't feel confident to be delved into the production, or even dev cluster, as not only there are used stateless applications, the most apps have to save their data in some external layers of data storage (I mean RDBMS, in-memory caches, etc.) and that is the knowledge gap for me on how to implement that. There is the tendency to containerize the db engines, too, as, IMHO, to complement the overall cloud-nativeness concepts and I know the StatefulSets simplify the solution.