> Events don't share mutable state (at least implicitly), they carry a copy of data. This eliminates a huge class of thread-related errors.

I'm not sure that's true, at least not in my problem space. Copying data leaves you the possibility of operating on stale data, which will result in the computation returning the wrong answer. To avoid that, you have to let the event handler know somehow when the data has changed. How are you going to do that?