The only reason you need backend-rendered apps is for SEO, if you've done the smart thing and built your business in such a way that you are not bound by Google's mood, you should be fine.
If you're stuck in eCommerce and absolutely have to rely on SEO to stay in existence, there are ways to get Google to index your single-page apps using the hash-bang operator, #!
developers.google.com/webmasters/ajax-crawling/do…