I don't see it as in I don't see anything in Slacks design that seems to be because of what you said. What incentive does Slack have to focus on metrics like "

I don't see it as in I don't see anything in Slacks design that seems to be because of what you said. What incentive does Slack have to focus on metrics like "engagement" rather than building a genuinely useful product. They just charge the customer for it, they aren't an ad driven social network like Facebook where "engagement" actually directly translates to revenue.