I just love the informal nature the docs take. I feel like I am being onboarded by a nice engineer. Consequently, this is how I write documentation internally. I like it more this way: it's a ton more fun to write than bland technical writing and it probably means the docs will actually get used and updated in the future.
I switched to fly.io not because of their excellent docs, but their performance with my service. I've tried Koyeb and railway.app before. fly.io was the best Heroku replacement.