I like SF&F because it is speculative. It asks, 'What if....?'
What if what we believe to be 'immutable laws of reality' are in fact mutable?
What if alternate realities exist and reality is only an agreement? What if it's an implant? Are we capable of being more than we think?
When humans eventually become a space-faring species, what will we find out there? What might other civilizations and life forms look like?
How far is too far to imagine?
Oh sure plenty of SF&F writing is awful dreck, derivative and poorly written, but that's true of every category of writing (it's time than winnows out the chaff and leaves only the wheat), and the best speculative fiction is sublimely imaginative and thought-provoking. It can expand our notions of what is possible, and what we are.
It is said, "A civilization is only as great as its dreams, and its dream are dreamed by artists."
When a literary artist writes speculative fiction, those are lofty dream indeed!
Jody didn't think in terms of genres, but that "What If...?" fired her imagination and intellect, sent her considerable abilities to the wild and far-out horizons she explored in her novels. It's why she wrote what she wrote, and why a lot of it came to be classified as "speculative fiction."