[jonas21]

The issue isn't that it takes a long time to parse the JSON. It's that the server can't do anything else while it's parsing. In Java, for example, you could parse the JSON on a background thread without affecting your ability to serve requests.

Similarly, the memory issue isn't so much that a single copy of the table takes a lot of space, but rather that they need to store 4 copies of the table -- because they're running 4 different processes in order to utilize multiple cores.

Both of these issues are specific to nodejs.