Which statement is true about platform events?

The statement regarding platform events that is true highlights their role in enabling event-driven architecture within Salesforce. Platform events are designed to facilitate real-time communication between Salesforce and external systems or between different Salesforce applications. By utilizing a publish-subscribe model, they enable developers to implement asynchronous and decoupled communication patterns, which is fundamental to creating responsive applications.

By leveraging platform events, organizations can react to changes in data or system states in real time. This allows for better scalability and responsiveness, which are critical in modern application architectures. Events can be published from external systems or within Salesforce, and subscribers can listen for these events, creating a robust, event-driven ecosystem.

The other statements are less accurate: platform events are not accessible through the user interface like custom objects, they cannot be updated once created because they are immutable, and while Apex can be used to publish and subscribe to events, it is not a requirement, as other methods, such as using Salesforce's built-in tools or external systems, can also be utilized.