A chord sequencer is an awesome tool to free up your left hand and either play a paino part with both hands or use both hands to controll an SA or DNC instruments solo.. Or just to have a drink with your left hand...

Its an awesome tool and its fun to use.... Its currently korg that has several of these tools build in as they aim at the pro players and their DNCs need much more controll then the Yamaha SA2 voices...

Do i need it? Well, do i need an arranger at all as i can play on top of midi and song files?