[lmkg]

I think by a "transpiling solution," he means something that is transpiled from (like coffeescript or dart), as opposed to something that is transpiled to, which is asm.js.

The problem with transpiled languages is that each transpiled solution is just one language. Many of them are nice, and almost all of them are improvements on JavaScript, but they're still just languages. Asm.js basically lets you use anything you want, which is an entirely different category of solution. In particular, it lets you use languages that already exist, for which you have experience and tools and libraries and standards and whatnot.