It is not too much to say Tokyo is the hottest spot for foreign adult entertainment lovers.

The first reason is service categories provided by Tokyo Escorts are incomparably more than other countries.

You can expect BJ or HJ as variations at the most in foreign escorts. In Japan, they are basic. You can enjoy genuine SM, and some Tokyo Escorts entertain with prostate massage and dry orgasm that are getting popular among foreign men through words of mouth recently.

I assume quite a few foreign men recognize Japan equals manga or anime. Otaku's paradise, Akihabara, is in Tokyo. There are many Tokyo Escorts where escort girls in cosplay of bishojo (pretty girl) characters in those 2D provide ecchi sexual service.
Therefore, it has enough VFM for foreign men to spend travel fee and come to Tokyo if you want adult entertainment with 2D characters.