When it comes to ground work ( fighting ON the ground), very few ( if any systems) can compare to BJJ.
WC does NOT compare to BJJ in terms of ground fighting NOR SHOULD it.
That WC CAN address the issue depends on HOW it is trained and VS WHAT it is trained ( hint: WC VS WC will NOT prepare you for ground fighting).
And NO, WC as it is does NOT have an answer for the ground fighting that a BJJ fighter brings to the table, if you ( or anyone) doubts that, they can test that view very easily.
The WC fighters best option is to keep the fighting standing as long as possible.