I use generators to stringify a huge amount (several gigabytes) of generated JSON for transmission over http/ws. Node can only handle about 1-2 gigs in a single string or Buffer -- it's a hard-coded limit depending on CPU architecture, AFAIK. So these huge JSON blobs need to be chunked.

A generator is nice here because it makes it easy for the code that converts the JSON for transmission to wait until the OS has transmitted the previous chunks -- which helps avoid catastrophic back pressure and runaway memory use.