For me, "smoothness" is more than anything else the result of good timing, and this is, I think, essential in Cajun music.
Playing in time becomes much harder when you constantly play octaves, because you have to change hand position all the time.
Every time you play a single button on a CA you are actually playing a double octave : every one has four reeds!
Playing octaves is nice, because you get a fuller sound, but playing in a flow is IMHO even nicer. And the expressive effect of an octave vanishes if you use it all the time.
Is this bullsh*t or makes it sense?