If you think that's the same as paying for sex then you need to grow up, and have a think about how you regard other people. Believing that you're entitled to sex because you spent money on a date is a super creepy attitude.
Then the women "decides" whether they have sex. At least I'm not so clear on how the second part of that secret handshake works. But it's very much a concept of paying a lot for things that are not technically sex because that would be illegal.
A lot of escorts will also take perfume, jewellery or other expensive gifts instead of money.
Just a quick google search yields this:
"It came to my attention on a recent trip to China that teahouses are now becoming the new center for scandal and prostitution. In fact, teahouses have had a mix meaning in China for centuries. Dating back as far as the Tang Dynasty teahouses were places to relax, play games and take in a traditional Chinese opera show. They were also a place where the equivalent of a geisha would cater to men by accompanying them with drinks, laughter and often-touchy behavior. Although this was seen as more of a custom to enhance customer service, it also gave customers negotiating room to ask the women for other services such as sex. Brothels were very common across China during this time and teahouses happened to be an outlet where prostitutes could also be ordered."