Why did the nine emperors pretend to be Xiao Chuhe?

The young singer Jiutaizi pretended to be Xiao Chuhe because Jiutaizi was going to the mountains to find the Taihe Temple. In order to better integrate into the local area, he decided to disguise himself as Xiao Chuhe in order to get better information. According to relevant information, you can also study other people secretly in this way, such as Mao Fu Mao Mu, without being noticed.