• SEO purpose
• Users see the page earlier
• Even better with caches in browser

In short:

• SEO - allows search engines to crawl your pages.
• Performance (initial load time).
• Cross device support.
• Same code base (sharing of logic).
• Non js users.
• Catching current trends ;)

In general, benefits for engineering, reusability, performance and SEO.

I have started to write a short recap about the subject, it's a work in progress but you can still check it out here:

https://github.com/saniko/Universal-React

1. Server-side rendering is friendly to Search Engine. Even though Google crawler can understand Browser-rendered page now, there are still other search engines that cannot.

2. Server-side rendering COULD have better performance if designed well. I use "COULD" since you may get opposite result if poorly designed.

To extend the question: Are preset properties (props) considered as good as server side rendering?

Google will love you!