I'll grant that the three are better than Slack alone. I guess.

But Jira is not good. Likewise Confluence is not good. It's more like bleeding out slowly rather than all at once.

What would be better? I don't always love GitHub, for example, but it hits these use cases in a far more effective and productive way.

I think you’re missing the forest through the trees. I like Jira for simple request processes and tracking projects. Confluence is nice because you can making a living document that is constantly updated. I see huge benefits using them vs not using them. It saves organizations a huge amount of time for knowledge management. Slack, Jira, Confluence are much better than using email and Sharepoint.