Why is Polymorphic relations important in Laravel applications, and what problem does it solve for developers?

Why is Polymorphic relations important in Laravel applications, and what problem does it solve for developers? The key reason to understand polymorphic relations is that Laravel applications are usually composed of several layers that must work together predictably. Polymorphic relations allow one related model to belong to more than one model type through a type-and-ID pair. Ignoring that boundary can lead to duplicated logic, poor security, unnecessary database work, or code that is difficult to test. Why it matters in practice: Eloquent relationships describe how models connect so application code can access related data using expressive methods instead of hand-building join logic for every use. The specific focus here is polymorphic relations: Polymorphic relations allow one related model to belong to more than one model type through a type-and-ID pair. This question is designed to test not only terminology, but also how the concept fits into Laravel's request, application, database, security, or deployment workflow.