I would never ignore you.
It's a valid question, I suppose. One is an issue of, I suppose, philosophy. There tends to be two approaches to fantasy writing; one where it's all about the story being written, and one where immersion in the world is also given importance.
Some writers will provide only the worldbuilding that's absolutely essential to the plot, with nothing beyond it, while others will prefer to give a sense that the story is only one of many taking place within a complex and fully realised world.
To illustrate, using invented languages:
For the first type, an invented "language" might consist of six words, created at random, for the single sentence spoken in that language. No thought given to grammar of any kind, as the language only features as a single sentence, and it's not worth it to put more effort in. Invent six words, and move on.
The second type may partially construct the language as a whole, developing words mostly as required, but also establishing some grammar rules such as conjugation of verbs, tenses, pluralism, basic sentence structure, and so on. The actual story might still only feature a single six word sentence, but a great deal more work has gone into the language.
I'm of the second type. What that means is, when I'm describing different martial arts moves and so on, it's not enough from my perspective to just invent a name on the spot each time, at random. I need to have at least a vague understanding of what each of these moves is, and where they might be relevant.
If
Vine That Catches is used to counter a lunge called
Heron Catches The Eel in one scene, I need to keep a track of that, so that if someone lunges at a character in another scene, they also use the appropriate guard, or that I don't have them uses that guard to counter an overhead swing.
Is it totally necessary? No. Is a reader likely to ever notice? Only if they read the book over and over, I would think. But I'll know. For me, maintaining the illusion of a comprehensive "real" world is very important, and so I need to be as accurate and careful with my continuity as a writer setting their work in a historical period, or modern times.
One of my reasonings behind this adherence to continuity is that I intend only ever to write within this one world, so anything I do now is an established rule for the remainder of my writing life. While today's book might only feature six words of that invented language, what happens if a future book uses it extensively, requiring me to really flesh out grammar and so on? If I haven't already established the most important rules for that first six word sentence, it's very likely that sentence will cease to be "authentic". That shatters the illusion of a consistent world.
Likewise,
Heron Catches The Eel might be a throw-away, flowery description of a fighting move today, but in a future book and entire character scene might revolve around someone struggling to learn that move correctly because their balance is wrong.
