Thanks for reading and posting a comment. Many things you mentioned are correct. NodeJS is the only option to write “isomorphic” web applications. But this post is specifically about “performance”. As you said, performance doesn’t matter for 99% of the web sites, because the load is fairly low. On the other hand when the traffic reaches millions of hits a second, performance begins to matter. Let’s say, we run 10,000 T2.large instances in EC2, that would cost $22,500 per day. (EC2 pricing https://aws.amazon.com/ec2/pricing/on-demand/). 30% of this cost would be $6768 per day which can be saved. If we consider one year, the savings can be $2.4 million. Performance is an important factor when scale increases.