Contrary take: Thank goodness! Finally a useful distinction between "we want to include you" and "you must interrupt what you're doing to look at this now, now, _NOW_!"

De facto other people already have control of interruptions, but with umpteen concurrent notifications (sometimes in multiple places, like DMs to say "did you see the notification in channel X / thread Y yet??" overlapping the original notifications), how to know where to focus? @ vs ! finally gives people a way to distinguish between inclusion and urgent interruption.