There's nothing wrong with your article as a tutorial on using CometChat. I think it was only problematic because of the lack of context here. For example, it assumes I know what CometChat is, but it's a blog post on cometchat.com, so that seems more than fair.
If it had been posted to Hacker News with a title like "Getting Started With CometChat and Vue," it would have been more clear. Posted to Hacker News under the title "Build a Vue Chat App" made me think it contained instructions on how one might build a chat app or perhaps a war story about someone who tried to build a chat app on Vue but ran into some interesting technical problems.
The tutorial itself actually looks pretty good. I appreciate the GitHub repo with clear "how to run this" instructions at the top and big, explanatory screenshots underneath.