After World War I, the five-nation treaty and the nine-nation convention were unfavorable to Britain and Japan. Why did they sign it?

During World War I, the comprehensive national strength and military strength of the United States were not as good as that of Britain, because Britain was a colony of old imperialist countries all over the world, and the United States quickly developed into a world economic and military power because of World War II, and became the world's number one power after the disintegration of the Soviet Union. After World War II, Britain's national strength declined sharply and became the second echelon country in the world after the United States and the Soviet Union.