Domain Events are not just for doing batch jobs such as sending emails or communicating to other Bounded Contexts; they're also interesting for performance and scalability improvements. Let's see an example.
Consider the following scenario. You have an e-commerce application. Your main persistence mechanism is MySQL, but for browsing and filtering your catalog, you're using a better approach, such as Elasticsearch or Solr. On Elasticsearch, you'll end up with a subset of the information stored in your full database. How do you keep the data in sync? What happens when the Content Team updates the catalog from the back office tool?
There have been people re-indexing the entire catalog from time to time. This is very expensive and slow. A smarter approach may be updating one or some of the documents related to the Product that has been updated. How can we do that? Using Domain Events.
However, if you've been working with Doctrine, this is likely not something that's new to you...