The main reason for not turning off notifications is the fear of missing out, decisions being made without you. And it's a very valid fear.
One team member going away from Slack is bad for the member and for the team. If everyone else participates and you're on the sideline, then you're an oddball and not a team player.
For it to be effective, the whole team has to willingly move away from it.
Do you all work at companies that don't do design reviews and code reviews? Those seem like good ways to keep people in the loop and get feedback on idea/code. Code reviews should be interrupts, but nothing else should be.
I find the amount of work one can practically achieve in a day to be a good limiter of how much people will be kept out of the loop if they are not actively engaging in their email (or whatever system people use). The reality is, no matter how fast you think you're moving, it's not that fast.
The point was that, if all of your team members are having a conversation, but you're not, you'd feel left out. Of course, you might not care, but a lot of people who feel they're active part of the team do; and discourse allows us to do that very well.
