Earlier quoted context omitted.
>Unless you run a private IRC server IRC has a long, tortured history of design-based security difficulties. So run a private IRC server? This is a weird caveat, like complaining that angelfire is an insufficient web platform and you have to run your own http server to do well. There are a billion IRC clients, libraries, and bots out there. There are IRC servers in most distros. There are JS servers in NPM. Why not u…
Companies are using Slack because they explicitly don't want to have to deal with this and would rather someone else take care of their chat infrastructure, and with more features.
We'd rather not manage that ourselves. It's just one more thing we can screw up.
This is different than the FOSS subject of the article, but it true that convenience is compelling.