The foothold at the city of Moroni allowed the Lamanites to continue their invasion northward along the eastern coast. While the defensive fortifications no doubt slowed their progress, they could not stop the army. The army was large enough that the Lamanites could continue to have an army sufficient to attack while leaving troops to defend cities where Moroni’s defenses had not been able to keep them out; they now provided protection sufficiently that they could hold those cities with less than the entire army.
The land Bountiful is the northernmost edge of the land of Zarahemla, and thus the Lamanites controlled virtually all of the land on the east of the land of Zarahemla, from south to north.
Verse 26 says that the city of Nephihah was taken, which appears to contradict verse 24 which says that Amalickiah did not come against the city of Nephihah. Although both the original and the printer’s manuscript have the city of Nephihah for both verses, it is possible that the mention of Nephihah in verse 26 is an error, and perhaps should have been the city of Moroni.