Since Japan and many North American countries seem to have a rather low domestic AC voltage standard (100V for Japan and 110-120V for North American countries), I am noticing that high wattage HX autotransformer ballasts and series choke ballasts seem to be more popular in Japan than CWA ballasts for high wattage HID lighting while in North American countries, CWA ballasts tend to be the most popular HID ballast topology for high wattage HID lamps.

I really would like to know why Japan seems to have a preference for HX autotransformer ballasts and series choke ballasts for high wattage HID lighting over CWA ballasts and why North American countries tend to prefer CWA ballasts for high wattage HID lighting instead.

Could be patent issue in the early days, after that just "we are using what we are used to"...

Other motivations:
The HX is still simpler (no reliability wise problematic capacitor,...), so while US had the desire to fix the problem of fluctuating supply mainly in the more remote areas justifying the use of that capacitor.
Japan used this lighting initially in more densely populated areas, where the quality of the power feed uses to be better (shorter distances, more customers, so easier to build and easier to justify to invest into more stable network), so the wider voltage tolerance was not worth the capacitor.