Why is the destination of the Beijing-Hangzhou Grand Canal Hangzhou?

During Emperor Yangdi's reign, in order to strengthen centralization and control the southern economic center of Huiji (Shaoxing), a canal was dug from the Jinghuai section to the south of the Yangtze River, with a total length of 2,4 kilometers.

by the time of the yuan dynasty, the capital of yuan dynasty was mostly (now Beijing), and canals had to be dug to transport grain from the south to the north. For this reason, three sections of rivers have been dug successively, and the horizontal canal of the Sui Dynasty, which was originally centered on Luoyang, has been built into a vertical grand canal with Dadu as the center and going south to Hangzhou.