Here's the problem with learning through fiction: the only thing you can learn about through fiction is the mind of the author. When you read a Rand novel, you don't learn anything about how objectivism works, you only learn about Rand's imagination of how it works. Similarly, sentience may in fact be mutually inclusive or exclusive of understanding; just because you can describe a circumstance in which something is true doesn't mean it can ever be true.
This doesn't mean that fiction is useless for learning about the world. It just means that fiction does not contain the tools necessary to decide if something is true (or accurate, or possible). Fiction may spark an idea or make an argument, but you must go outside of fiction to see if those ideas have merit.
Granted most fiction wont provide an objective audit of views on any subject, but to say that the only thing you can learn is the mind of the author oversimplifies the cognitive process that takes place during reading, as well as the issues addressed by fiction.
Reading in any non-topical sense forces you to evaluate what you are reading and helps create those new connections in your brain. At the same time, many of the deep issues addressed in fiction are completely outside the realm of factual verification.
There are two main pieces to our perception of the world - the bare facts and the larger picture you get from combining the facts. The larger picture is more universal than the bare facts, so it is more useful than a use case.
Plus, and this is often ignored today, big pictures are not entirely mutually exclusive. To use a comp sci analogy let's look at search algorithms:
Use cases are more similar to deterministic partial solution searches (backtracking depth first search, breadth first search) for which the more interesting problems are intractable. Additionally, such search algorithms are very self contained, and it is usually quite difficult to combine them, making these algorithms a one time tool.
On the other hand, big pictures are more similar to stochastic solution spaces searches, which won't get you the best solution, but they'll get you a pretty good one much, much more quickly. And since solution space searches all interface with the same space, they can be mixed and matched depending on what is most useful for the problem domain. For example, with genetic algorithms, once you can make your problem domain fit a standard GA representation, the whole of GA theory can be applied.
But that's also the beauty of fiction in some contexts is that it allows one to explore ideas outside of their usual context and often within the realm of suspended disbelief.
Aldous Huxley, for instance, both in his fiction and non-fiction, and I see no great gap between them other than the mechanisms employed, has profoundly shaped my thought with his writing.
What about fiction that simply describes how people feel, act and behave? Not every story has to be a metaphorical attempt to explain some philosophical concept.
This doesn't mean that fiction is useless for learning about the world. It just means that fiction does not contain the tools necessary to decide if something is true (or accurate, or possible). Fiction may spark an idea or make an argument, but you must go outside of fiction to see if those ideas have merit.