That's what I've been doing as well. No "certificate of accomplishment" at the end of the class, but still the benefits of learning the material. Seems like a fair trade.
In my opinion, the real learning comes from doing the exercises. So if you are reading the material but not doing any quiz or exercise, you aren't learning as much. And if you aren't doing the exam, which has a time limit and you can't repeat until you get it perfect, you don't know how much you are or aren't learning.