We started using slack just for our dev/eng teams at work, and the interest grew to some of our customer side teams and non-technical teams, but management have been reluctant to expand Slacks licensing. Then we realized Teams is included with our MS licenses, so now we're giving the non-dev/eng side of the company that. It's only a matter of time before someone with a little sway asks "Why are we paying for this when we have Teams?" the murmurs have already begun, it just has to hit the right ears, so the days are numbered.