Both bottons look elegant. Probably your botton was posted at a wrong time of a day. That's why I've made an app that tells you when it's good time to post a story. Today 9am, a lot of newest stories were upvoted quickly - biggest peak in over two weeks.
It would be nice if clicking the button made you a watcher.
I think the reason for the difference is this one was so simple. From the title, I knew what it was going to be. With yours it was a little over complicated. From the title of HN post, to the website
It would be nice if clicking the button made you a watcher.