In graphic terms, insight is like the proverbial tip of the iceberg to the process of writing. Beneath the tip is the whole sum of effort that is required to ensure that writing gets to see the world. Much of what takes place after insight has long gone is hard work, tears and blood so to speak that make writing becoming real.
Of course, for great writers, insight has its part to play. But the fact of the matter is that insight is not always available. In itself, insight is highly ephemeral. It can be like the passing wind.
So it is the effort that has to kick in to ensure that the insight can remain alive to see the light of day.