... the arranger automatically mutes the style piano Part. Ditto for horns, organs, whatever.
Nice feature on the Korg arrangers (PA series, at least ...) the assignable buttons can turn off the bass part, or the arranger tracks with one quick push.
There are 3 buttons on the PA900 - I have them configured to do it this way:
#1 turns the LH sound (manual bass) ON
#2 turns the acc bass OFF
#3 turns all the arranger tracks (1-5) OFF
This way ... even during a song, I can switch modes with ease and a quick button push arranges the keys the way I need. I will often switch off all arranger tracks in small, quiet rooms ... too much fluff for a background situation, sometimes. These 3 buttons are a great tool for me. LOVE 'em!