Setting aside the fact that many works of speculative fiction are groundbreaking, important (however we define it), subversive, brilliantly written, entertaining (and never underestimate the value of entertainment as entertainment), and what have you, for me the entire genre does something much more important, separate from those factors — it exercises the imagination, fires our sensawunda, expands our sense of the possible, and encourages us to dream heroically. I think there’s enormous value in that, and all speculative fiction does it to one degree or another.  The rest is details.