Well, pretty much every product starts out as a proof of concept or a prototype. Both of those things you mention prove that something specific can be done in javascript. And I can say that they were pretty helpful to my partners and I.
"... wonderful intelectual (sic) excercises. Probably not products ..."
Wrong.
If you read the article carefully, you will see the code was used to produce a rather nice interactive digital book, *"Eloquent JavaScript: An opinionated guide to programming" ~ http://eloquentjavascript.net/chapter1.html
Let me guess, you?
I remember seeing a 3D JS/DOM 1st person shooter and a raytracer in JS, wonderful intelectual excercises. Probably not products.