What does this enhancement do?
There are project or ticket related events that do not currently trigger an email notification.
One example of this is users commenting on a ticket but there may be others.
It is hard to say whether or not "all" events should drive a notification here, so this may be intentional.
In this case, the ability to determine the granularity (groupings) or the specific events (full control) of which events generate a notification would be preferable.