Out of the incredible volume of emails I get, if it's important I'll either be watching for it. Or someone will instantly come over to my desk asking if I looked at it. this seems to be a trend at every company I've worked at dating back to 90s.

Email is also a tool that can be misused.

So is a circular saw. But between the 3 options, one is a clear winner for the topic at hand.

>misuse

You mean, using it how the designers expressly intend it to be used?