I use writing (or even speaking) as a tool to sort my thoughts, because they tend to stay afloat until I can put them into words. It's like they don't properly manifest or become truth until I bring them out in some way. It can lead me to new considerations/conclusions in the process of writing, too. Sometimes it's still hard to find the right words or expressions too, something I ought to keep a better overview of in the future as well. So in the sense of having an "overview",
@bonfire may be right in saying it has to do with Ne. But perhaps we should consider that there is also a different relation to words and word uses in different types, before claiming that someone is more or less eloquent (sorry, "claiming" is a strong word, I don't mean to accuse you of anything)? I think the capacity or potential is there for anyone, but it's the way of thinking (and a couple of other factors) that have an impact on expression. Ni (or even Si) could perhaps be used to be precise in expressions, but the way of thinking (function use) may make it look differently because of how the register is ordered in the mind, be it associative, conceptual, analytical or any other way.