Redactive analysis: The separation of these nine verses into a separate chapter highlights the anomaly of their content. We have just finished Nephi's relation of his father's dream, and we are about to begin Nephi's experience with the same vision. Those two events are inextricably linked, and the presence of this mundane text in between the two spiritual discussions is odd indeed.
In the original version of the text, which separated chapters but not verses, this information is tacked on to the end of the Lehi vision, and the Nephi vision begins the next chapter. The placement of the verses there confirms that these serve as some soft of transition, but what kind?
I have indicated before that Nephi uses the Book of Lehi as a springboard for this version, but that he vacillates between a more historical recounting of the Book of Lehi, and a very personal account of the way those events affected him. I believe that in these verses the explanation of the composition of the plates serves as a marker indicating Nephi's clear intention of continuing on a much more personal level, and his leaving off of pretensions of copying the Book of Lehi material. The transition comes between a quintessential experience of a patriarch (a vision with a message for the family, as well as for posterity) and Nephi's personal experience with the same vision. From this time on in the Book of Mormon, Lehi begins to fade even further into the background, and the book clearly becomes Nephi's. With these verses I suggest that Nephi understood on some level the transition he was making, and justified it by indicating the nature of the small plates.