Property Hell

Among the myriad of shit i do not understand about property...one thing that really bugs me is that we have been learning rule after rule for the last 3 weeks...each of which is super complicated and involved (at least to me)...and then at the end of this confusing maze the book says "this has now been overruled"

WTF?!? Why do we need to learn rules that are no longer used? What is the purpose of this? To torture us?