Fundamentally, it's a demonstration of equality: “We are the People's Republic of China. We can do what the United States can do. In fact, now we're ahead of them.” It's about prestige and humiliating us. If you go back to the space race between the Soviet Union and the United States, a lot of that was simply a race to the moon for reasons of prestige.
On June 3rd, 2024. See this statement in context.