Because all is based on registrations (performances in Korg's language). Very usefull if playing kb is your first job and you have a lot of time to program all the settings you need. If not, you will need several months to make your kb operational.
And do you know what?
When you are ready with it, it si too late because they are new kb more powerfull, with more features, and new fantastic sounds...

hehe that is called trade.