One of the best aspects of CGI is how easily tested a CGI program is. All you have to do is set a couple environment variables and connect your request entity to stdin, expecting things on stdout. What could be better?
Was also easy to "verify" contents of /etc/passwd and /etc/shadow. cough cgi-bin/phf cough
That's not the fault of CGI but rather of the people who wrote bad code. You can easily have the same problem in your NodeJS express app if you're careless!
The best FAAS framework
I remember creating a web query form for an employee search or something like that using CA Clipper and reading stdin an spitting our HTML on stdout. Worked like a charm, was fast and made that data available to whoever needed it.