I’ll just add one thing to clarify. One can absolutely use manually created Custom Events with an Event Dispatcher but you must ensure that the signature on the dispatcher matches the event’s one.
All the dispatcher assignment does is to create a custom event with a matching signature and correct attribute names; Automagically so to speak.
If the question was: “What is the difference between the Event from the dispatcher’s event list (the original pic in the question) and a Custom Event”:
The answer would be: It’s a shortcut. Apart from that there is no difference afaik; but you need to manually punch in a list of attributes if you’re not using automated assignment with the context sensitive blueprint wires.
That event list takes care of it all by making the events available in the owning actor and provides pertinent pins.