Well as per the article (and my own experience), the free tier only gives you public channels. The paid tier gives you everything: public/private channels, grou

Well as per the article (and my own experience), the free tier only gives you public channels. The paid tier gives you everything: public/private channels, group chats (called MPIMs), and one-to-one DMs. So yes, it breaks "privacy" (not that you should expect privacy when using a work Slack account).