I use it so that I might fully understand it. I have found that even though I think I fully understand a passage, I have missed something by viewing SparkNotes and seeing what’s there. I don’t think that summaries should be used as a substitute for reading the actual work, however. You should read the work first and then look on SparkNotes to summarize what you just read and briefly analyze it so you can understand it better. At least, that’s what I do and I find that it works well. I know it might take a little longer, but being lazy is a choice.