Stream of Consciousness

We had to read a novel that was written in the style known as "stream of consciousness." As I was reading people's comments on their interpretations of the novel and whether or not they liked reading "stream of consciousness" I started deciding for myself whether or not I liked it. I think I can understand why people write that way. You can write down whatever comes to your mind in whatever order these thoughts appear. I used to have to do this in High School for journals in my English class. If we couldn't think of anything to write about our teacher used to tell us to write down whatever came to our mind. But what if I don't think about anything or what if it doesn't make sense? Is stream of consciousness an effective writing style for the reader? While it may be perfect for the author because they don't have to spend a lot of time deciding what they want to write about it sucks for the reader because they have to make sense of the whole text which might be nothing more than a bunch of words.