I won't question that this group were skilled and schooled musicians capable of following an arrangement with precision.
I'm no Ginger Rogers, but it seems to me that dancing to this band would be a wearying chore, with that jarring plink-plink-plink-plink rhythm. Except for the solos, it was a chore to listen to the whole song. It's the musical version of doggerel verse!
The reason "it don't mean a thing if it ain't got that swing" is exactly the reason that people were crazy to dance to music that swung. If it's good, swingin' jazz, you can't keep your feet or body still, even if you are sitting down. You become part of the music and can move and not grow tired because the music just lifts you up and carries you along with that beat.