Im no world leading expert but as far as I understand, coupled with events, if an unimportant service goes offline for 5 min (due to some crash, ie "fault"), its possible to have a graceful degradation, meaning the rest of the system still works, maybe with reduced ability. With events, other systems simply stop receiving events from the dead service. I agree you can achieve a lot of this also in a monolith with try catch and error handling, but I guess there is an inherent decoupling in having different services run on separate nodes.