1 Nephi 1
It sounds like Nephi felt prompted to make this record partly because his life had been good despite his afflictions whereas if it had not been filled with afflictions he may not have felt he had anything to say.
Nephi tells us that he will not make a full account of what Lehi saw in vision. I’ll bet that a more detailed account was found in the Book of Lehi that was stolen and possibly an even fuller account was had among the Nephites for Lehi’s own writings. It’s interesting to realize that Joseph (and his first scribe(s) as well) must have known a few things from those early pages of translation which shed even more light on the story of Lehi and the time in the land of Nephi.