I just sort of read through that manual. It seems to me it would be easier to just put the text files in the Korg, associate the correct song with the Songbook entry and save all that trouble. I assign text-down to one of the assignable buttons. Only thing I can see that the tablet would add would be larger display and print.
Oh, it just hit me--I guess if you want to display scores that would be a valid reason to use the tablet! Duhh!