What is the origin of the idiom "more holes than Swiss cheese" and when to use it?

The idiom "more holes than Swiss cheese" originated from the fact that Swiss cheese is a type of cheese with distinctive holes or "eyes". The cheese is made by introducing bacteria into the milk, which produces gas as it consumes the lactose. This gas forms pockets within the cheese, which eventually become the holes. This phrase is used to describe something that is full of flaws, inconsistencies, or errors.