Why do Japanese hotel girls kneel to serve their guests?

This is called the earth seat, which is a kind of etiquette to show respect.

どげざざ is a Japanese etiquette, that is, an apology or a petition. In ancient times, it was used to show humility to people with high status. In modern times, it is generally used to express the deepest apology or sincere request.

It's not the same as kneeling in China. It is a form of Japanese etiquette, and its expression is full of enthusiasm, which is used to strengthen the formality and attention of any scene. Apologize or petition, because the national conditions are different, there is no concept of having gold under one's knee, and you can also see that Tosuke Tushimo is often used in various Japanese dramas.