I'm sure there's a use case for this but, for me, it's pretty rare to need pull new data or persist anything after most events, let alone every event. A single fetch and single save is usually all that's needed.
Whenever any information needs to be saved or processed by the server, you can perform your server-side logic inline in the event handler (e.g. update the database, contact external services, etc.). There's no need to make an AJAX request and have a corresponding API route. This abstracts away the client-server interface, and you get safety guarantees with type-checking.
