For what reason did President Trump suggested U.S. - North Korea dialogue?

I believe that ending the Hanoi summit without a deal was a strategic misstep. According to reports, Kim Jong-un had prepared a mass rally in Pyongyang for that occasion; he had planned a grand welcoming ceremony in anticipation of reaching a favorable agreement with President Trump. He sought to craft a narrative—contrasting himself with his grandfather, who fought a war against the U.S., and his father, who engaged in a Cold War—by portraying himself as a "great leader" who overcame that history to achieve reconciliation with the United States. He also aimed to secure his regime's legitimacy by fostering economic development with American assistance. In a sense, because both the U.S. and North Korea effectively shut the door on each other at that time, no progress was made on the nuclear issue for years; instead, it served as a catalyst for North Korea to dramatically advance its nuclear capabilities. When it comes to resolving the issue, wouldn't a policy of engagement have been more effective—or at least offered more room to create alternatives—than a policy of non-engagement?

I am not concerned with the political motives behind the President's assertions. My focus lies on the benefits this policy offers the American people and the impact that establishing a peaceful order in Northeast Asia would have on global peace and prosperity. I look forward to hearing your valuable insights.