Textual: This is Mormon's summation of the end of the festival. We understand that Mormon's purpose in including these sermons is spiritual, not historical. In a significant renewal event including both the naming of the people and the anointing of a new king, Mormon is exclusively interested in the spiritual transformation of the people into a new covenant society united under the name of Christ. Thus we have this single sentence to cover what were surely other significant events taking more than a single day to complete (particularly the census as noted above).
Anthropological: Note that as the multitude is dismissed and the festival ends that all return home according to their families. Once again we have the subtle emphasis on the organizing power of the kin group. In this case, we have the kin group associated with their "homes". Reading between the lines of this simple statement we have confirmation that Benjamin's people followed the typical Mesoamerican pattern of kin-based housing clusters. When each individual returns to his own house according to his family, the implication is that housing and families are geographically linked.
In Mesoamerica, this pattern continues to the present in more traditional communities, and can be seen archaeologically in the types of shelter/temple groupings in many sites.