From what I can see the only thing it does above and beyond Slack's own integration is generate images. To me that's the most low-value part of the value proposition.

https://www.salesforce.com/news/stories/slack-news-dreamforc...

OpenAI also has a teams product:

https://openai.com/blog/introducing-chatgpt-team

I mean, I understand, it's an internal tool and all, you're not building a business here, out of this tool, but I'm going to guess that you end up ripping this out within months as Slack invests big bucks into integrating AI into their platform.