Web Assembly is not meant to be a replacement for JavaScript. And although the blog doesn't explicitly say it, it's alluding to it being easy to create entire applications without using JavaScript at all.
JavaScript is going to continue to be used as "glue code" at the very least, and UI code in the majority of cases. I think it's really important to make this distinction.
Trying to use web assembly as a solution to problems it's explicitly not meant to solve is only going to lead to pain and frustration.
Furthermore, things like "static type checking", easy functional programming, and making application coding "less painful" aren't really goals as the post seems to make them out to be as well.