It does most of what you describe (connecting/disconnecting from a running Arc repl). I don't know if you can use it to save cron jobs, but that's not something I typically need to do.
Yes, I use screen very heavily, and I do use it to leave an arc process running, and connect to it again later.
But it can't connect to an arc repl that was executed by a non-interactive shell, such as via cron or initd. That's what I use the pipe system for, and a similar system could easily be used by an ide to communicate with arc and not create a visible shell window.
