Scott could you elaborate a bit more on this topic? Using SMF w/lyrics/score, custom or commercial is a big part & very strong feature of using an arranger KB....weather you just sing to them, play with them, use them for a band backup or to accomp you on big multitrack arrangement songs that are impossible to play in style mode alone. Playing an arranger vs an acoustic instrument is all part of the fake game in a way .....when you play styles your LEFT hand chords trigger a pattern that the Kb plays the style parts, drums, bass, etc, etc, no one thinks YOUR playing all those parts when they hear a band & see one person playing some kind of electronic device which leads to their thinking Karaoke, Computer, iPOD, CD's, Casio kb or some kind of musical device to generate the sound the audience hears...these are the downfalls to today's audiences perception of a One man band scenario & n today's world this isn't gonna change but get worse .....
Lip syncing, Air guitaring, fake playing & singing is part of the show in many big acts all over the world, eg: Disneyland, Vegas, etc etc the audience knows that BUT they love the Show because its entertaining, Looks good, & Sounds good & that's the bottom line to a paying customer leaving satisfied that they were entertained for an hour or so, feeling good, forgetting their worries, & enjoying their time during the act. An arranger KB is just another musical tool to be used in anyway to generate happiness musically. I find Purist attitudes boring sorry.