TOPIC: Show Details Link Question

What does this do?

On the Event Registration page, should there be a link to the JEvents event?

I don't notice any difference if the setting is Yes or No for a given event.

That "Show Details Link" will add a "Details" button on the event listing page IF you have selected an article for the event... which is done just above this parameter. This is so you can use an article to provide more details for the event. Video tutorials show and explain this too. This setting has nothing to do with JEvents.