Hi John,
I have no idea why anyone would want to record in other than the key of C , only know that it’s possible.

Maybe not necessarily the best key for Eastern music ? really don’t know. A lot of non western Korg owners create their own styles. Maybe they need choice.

Only time I might use it , would be if I was using a couple of bars from a midi file track to create a style track or even a multi pad.
Easier to set the correct scale and chord type, in settings , than transpose the file.
If the settings are correct the keyboard will follow and do its job .

I think even our SX styles can be recorded in different keys if one needs to

Quote page 22 reference manual


Set the Source Root/Chord if necessary
Although the default Source Root/Chord is set to CM7 as described above, you can change this to any desired one in which you can play easily. Call up the “SFF Edit” display, set the Source Root and Chord to the favorite or desired Root and Chord type. Keep in mind that when you change the Source Chord from the default CM7 to another chord, the chord notes and recommended notes will also change. For details, refer to page 27.

Makes interesting reading for anyone interested in recording styles.