A FIML query shines a laser beam of light on a single data-point which has psychological importance for both partners.
In this respect and very importantly, a FIML query is unique among all speech acts. There is no other kind of speech act like a FIML query.
It is philosophically unique, psychologically unique, intellectually and emotionally unique, and linguistically unique.
The main reason FIML can be difficult for some people to learn is a FIML query is a unique speech act, not just a unique sentence or insight or idea. The act of making a FIML query with FIML intent is an act unique in human history.
This is not a trivial point.
It is not trivial for reasons stated above and also for the following reason: there exists no other way to accomplish what FIML accomplishes.
If you have tried FIML and found it odd or trivial or believe it is something you already do, or if you found it frustrating or petty or needlessly opaque, please think again.
FIML is mainly hard to do because you are doing something you have never done before.