I see asm.js as the Revenge of Compiled Languages. Coupled with generic interfaces for accessing underlying graphics and audio hardware, we're just right back where we started with Java applets. Write your apps in whatever language; run in the browser.
One cool thing about JS is that you have runtimes for it in computers, tablets, phones, TVs and most current videogames so you can experiment and build stuff for a variety of hardware that no other language can reach as easily (of course you can reach anything with C but it is not easier).
Remember all that could be done in JS two years ago and all we could do now. Imagine by the end of the next year what we'll be able to.
I don't care if people are using LLVM to cross-compile other languages to the JS runtime, this kind of approach and research makes better runtimes and both camps benefit, the people who hate JS can use their fav language and those that enjoy JS end up with a better runtime.
As you say getting other languages to run is a good thing because those who don't like JS don't have to use it (or indirectly use it with stuff like Coffeescript).
IMHO most people that do not enjoy JS is because they approach it from a mindset of an OOP programmer. People try to treat it like Java or approach it like a toy language to cook quick jQuery script then they feel frustrated. I am not saying that JS is everyones cup of tea but some people like me enjoy it.