PPC Campaigns need to have fault monitoring in place because they can run into fault conditions.
For example, the credit card on file to pay ad spend may expire. Or a bot may flag an ad and disable it.  Shopping products may develop price mismatches.
In all of these cases, we catch and resolve the issues quickly because we monitor all campaigns under management.
Our campaign monitoring system notifies us in real-time when there is a fault, so we can fix it immediately.