I spoke with a (potentially biased) member of technical staff @ Anthropic today who claimed that tags w/ multi-player capability is the biggest thing they've shipped since Claude Code.
Although I suppose the problem with doing it for Cowork is this is a slack plugin, and that is not where most non-tech companies are. Teams is, at 320+ million active users vs. ~50 million.
Everyone hates Teams, but like or not that is where enterprise work happens, not slack. Anthropic would do well to make their Microsoft 365/Teams integration story better and go after enterprise before OpenAI does, or before Microsoft catches up (if they ever do) with Copilot.