In scenarios with multiple competing answers, I imagine upvotes and marking answers as helpful/correct, would help surface the best ones. In our case, most Qs have simply one answer, or some clarification comments, so SO adds overhead.

1. We can have a single source of truth for questions 2. The Slack integration for easily seeing activity 3. The onboarding partners were super helpful 4. The tag management system is great - I can subscribe to the tags I am interested in 5. Voting is sweet - allows us to look at valid answers

The ease of use due to brand recognition and familiarity. A lot of other competitive systems tend to not support absolutely basic features like syntax highlighting, markdown, etc... which are crucial for technical documentation. The navigation of the site also obviously benefits from being derived from a public site with years of refinement.