We (small business with 7 employees at desks and another 5 on the floor) use it exactly the way you suggest. As the sole IT staff, I get the most messages from the other employees, and send out the most, with the company president close behind me. Two online sales staff, the lead shipping clerk, and the physical store manager follow from there. The warehouse manager doesn't bother with it, and the CFO detests the idea of it (she's also one of the oldest team members at 49).
Most communication is by email, SMS/iMessage, face to face (though we are reducing that due to current concerns), 2-way radio, and phone, in that order. Slack is mainly for sharing the odd file or link, or for staff to reach me for computer related issues that require me to see something rather than hear it (screenshot, etc). We could go with any other messaging service, and before Slack we used Skype, but Slack at our level is free, easy, and runs on all platforms we use.
The idea of it "replacing" email, phone, and radio comms is ludicrous to us. I can't imagine how it can work that way in larger organizations.
My team of 200 people's sole form of communication is in slack. The only emails we get are calendar invites to meetings.
I genuinely don't understand the problem with that. Slack is great- it's synchronous when you want it to be, and it's asynchronous when somebody is busy. It's easy to search through stuff, and since all of the other teams in my company use it, I can reach out to anybody in the company at any time.
Most communication is by email, SMS/iMessage, face to face (though we are reducing that due to current concerns), 2-way radio, and phone, in that order. Slack is mainly for sharing the odd file or link, or for staff to reach me for computer related issues that require me to see something rather than hear it (screenshot, etc). We could go with any other messaging service, and before Slack we used Skype, but Slack at our level is free, easy, and runs on all platforms we use.
The idea of it "replacing" email, phone, and radio comms is ludicrous to us. I can't imagine how it can work that way in larger organizations.