How we ended up choosing Confluence as our internal web / wiki / documentation platform at Katana.
It happened because we chose Bitbucket over GitHub . We had Katana's first hackaton to assemble and test product engineering platform. It turned out that at that time you could have Bitbucket's private repositories and a team of five people for free - Done!
This decision led us to using Bitbucket pipelines for CI, Jira for Kanban, and finally, Confluence. We also use Microsoft Office 365 and started with using OneNote, but SharePoint is still a nightmare product to use to collaborate, so OneNote had to go.
Now, when thinking of the key value of Confluence to Katana then it is Product Requirements Management. We use Page Properties macros, integrations (with Slack , InVision, Sketch etc.) to manage Product Roadmap, flash out Epic and User Stories.
We ended up with using Confluence because it is the best fit for our current engineering ecosystem.