But doesn't ruby on rails (and most other web stacks) already do server side rendering VERY well and are hugely supported by enormous communities. Javascript is useful for things like infinite scroll, interactive client side calendars or making browser based games; but a web search is absolutely simple in ROR and doesn't need backbone or javascript at all.
Don't get me wrong, I love javascript and backbone / angular. But why push logic to the client side for a search page and then try to pull client-side technologies back to the server side in an effort to resolve performance problems that are already solved by existing technology?
In the words of Carl Sagan "why not skip a step". Unless you just love javascript so much that you're willing to recreate rails on the server side with it. That would be a sensible reason to do it.
Not trying to troll, just thought I'd throw this perspective out there.