The cable chop sounds great on paper, but when it comes to the execution it's less of a core exercise and more of an arm blaster. Also, the resistance changes drastically from beginning to end.
With this method, the Swiss ball acts as a cam similar to what you'd find on a machine, giving you the feel of constant, equal tension throughout the ROM and putting that tension right where you need it.
For this mechanical drop set, you'll start with the hardest exercise and, as you fatigue, move to the easiest. Works with a bar and a supinated grip too.