Disclaimer: I am a consultant working for an Atlassian-centered consultancy. I do a lot of Confluence-based projects recently.

You would not believe how special some use-cases are, especially when you work with organisations that have highly regulated environments. I've seen anything from markdown files in a git repository being semiautomatically created in a Jenkins run to an organization having built essentially their own wiki software because nothing on the market fulfilled their need at the time (now 5 years later, they realise no-one uses that thing because it is just unintuitive). I have seen organisations that have no content oversight and some who had a whole department of "content czars", whose sole job it was to keep their documentation fresh and updated. I've seen organisations that had strict rules on approving each individual change, with complex approval workflows.

If you have never documented anything, Confluence may be overwhelming, but so will every tool that has "sensible defaults", because before too long, you will start hitting the envelope. Documentation software is not like a MacBook that you just buy and start using, you always need some level of customisation.

So, is Confluence damn good? No - there's a lot that could be improved. But from the mediocre solutions on the market today, it is one of the better choices.