Diki,

this is nothing like karaoke
it's the actual vocal from song, not a sound alike
which is playing in sync with Audyas rhythm
while following chord changes on keyboard,
which pretty much gives you freedom to mix, extend, arrange, etc,
karaoke is preety much a midi file, audio file, starts at 0 end at 3, next, etc,

this is an arranger with an audio vocal in backround
while it may not be useful for most, it may be for many

i think it's a nice and unique use of keyboard