You don't need to justify your library to anyone but yourself.
Not every book needs to teach you some fundamental life lesson for it to be worth your time. Thinking like that is a quick and easy way to burning yourself out. Let your hair down and relax with it. Take it to bed with you and loose your imaginations. Have fun they way you want to.
I find the idea that you need some other "justification", or that some justification might lead you to continue to read science fiction when you don't enjoy it – to be a "wait, what?" kind of question.
― Bertrand Russell
--
If you don't enjoy science fiction then don't read it. If you are a looking for a reason to do so, then stop - it's wrong.
#
As for why read sci-fi? Well, there's a lot of bad sci-fi out there. At its best it represents interesting explorations of the effects that changes in science, context, and or very other social structures can have when they interact with human societies - and in that much perhaps tells us something about ourselves and where we might be going. Accelerando probably falls into that category, Blindsight would be another, Dune.