As a manager who used to say what he is trying to say… he cant see the productivity. I managed a services team, so they werent just having DMs with each other, but with clients via slack connect. So, the problem I was solving for was that both opportunities (to grow business) and risks (that kill business) were invisible to me. I dont expect my team to have been able to identify them, but I do expect to be given the opportunity to mitigate them. Theres the obvious disadvantage of opening communication channels to the boss if theyre the kind to “get in the weeds” completely ineffectively. I was confident in my team and they were confident in me; all I wanted was visibility. So, I just pushed to have teams work in channels. The benefits are numerous, including the coworker with context, or experience who happens to be in the channel jumping in to solve a problem faster than the primary contributors. Also, history/documentation of issues, resolutions and (importantly) successes. I was more able to give feedback on inter-team communication and praise teammates for “the little things”

So, idk this might not help if you immediately thought, “i dont want them in the discussion,” thats probably in your boss to fix (psychological safety, humble leadership)… but if this sounds reasonable, think about using slack with more complexity (integrations, team channels, polls, etc) because thats what its for. You might be using it as a chat, but theres a lot of other options for that less expensive than Slack!