It's truly shocking what you are trying to tell here! Perhaps Wersi uses the methods you describe but there is one thing I know for sure : The Yamaha Tyros(x) demo's are played without external instruments, sequencers of whatever.
Why should they? ..... this is the way Tyros3 sounds and is playable for all real keyboardists.

It's obvious you are a Wersi-fan, but your statement 'Wersi can do it much better' makes me smile.... please wake up!