The America/Korea Summit came and went in a flash. The result was a letter of agreement (which was obviously mostly drafted in advance) between the two nations. So far as I can see — and this is a very quick take — what we really gained was a better relationship with North Korea.
The major benefit to the American people in this agreement is that war is now off the table. The rest of it is a letter of intent with no enforcement other than the integrity of the North Korean government. North Korea agreed to work toward a nuclear free North Korean Peninsula, but there is nothing in the agreement such as a time-table or inspections to keep them honest.
President Trump has agreed to stop military exercises in the region, which is something China has demanded for a long time.
If you want to read the agreement letter between North Korea and America, go here.