Bigfoot,
If you are in the middle of a song and you want to switch to different settings (i.e. different style, transpose), if your keyboard has reg memory ability then all you have to do is press that button (that you already set beforehand) and everything will change instantly !

Yamaha: You do have a point about the novice probably not caring so much about reg memory. After all, they are beginners. But for me, that is a big oversight IMO and the keyboard is unusable for performance. Yamaha does have nice feel and sounds especially DGX300 which has superb key feel that makes me love to play the machine.