What are the pros/come versus using a mature online editor such as Cloud9, that supports direct terminal access to the backend instance and FTP/SFTP support? Though I will admit I was disappointed when AWS acquired Cloud9.
Good question. Repl.it is all about instantness, you should be able to get a REPL really fast[0]. If you want to host a webserver you should be able to do it quickly from the same interface[1], if you want to share your work then that should also be possible[2]. You could code and ship a small webserver on Repl.it faster than you can sign up for Cloud9. Repl.it is also what's no called "Serverless" in that it's logic…
Maybe it's because giving away cloud services for free is not a sustainable business model.