It does depend on the use case. If you have a website that requires authentication, you can load the whole code while the user logs in. In that case, SEO is not an issue either already now. It also does depend on your market. Certainly there are some markets where you might have to eek out every last bit of reduced latency. But if your market is a country where nobody has a connection of less than 10MB/s on their desktop OR phone then you can have a 1MB codebase plus stylesheets compressed to ~500KB and served by SPDY/HTTP2 downloaded, decompressed and running in less than 250ms. Why would you then ever go through the additional work of rendering on the server?