You're 100% right but you're missing something here. Something like this takes skill and builds skill and when you've finished you just want to show it off. And it really is impressive! Sure, it has no practical application itself but I'm sure that some piece of this or some technique used in porting it to JS will have some practical value somewhere. Sometimes the practical is born from the impractical.

I guess what I'm saying is why does it need to do anything or be practical? Cool stuff is just cool sometimes.