All I can say is this girl is like many PS in that you are paying a premium for the fame. In this case, she is at a high-volume spa instead of hotel room, and so the price is roughly about 1/3 that of a typical American PS booked through an agency (but 2x rate of other girls at that spa). Her skills are that of a typical Japanese pro - which is to say, pretty basic. There isn't really a "skills premium" - a girl that is priced at a premium is most likely for fame, or a uniquely attractive body type (or in the case of many twitter indies, absurd gen z arrogance).
The argument that JAV stars may be cheaper in Tokyo is irrelevant because nobody here is buying a plane ticket to Tokyo and I doubt 90% of the posters on this board speak Japanese well enough to even book a girl outside of the few English-language agencies that cater to gaijin.
Despite her surgical adjustments, Mion is uniquely attractive relative to other girls generally and has a unique body type. Plan your visit accordingly.