This is a tool for beginners. Formatting code on save might cause confusion. IMO professionally format on save sounds good if your expecting it. For a beginner they should learn the syntax and concepts. Formatting can be taught later.
There is a world of difference between tools for learning how to code and tools for producing code.
Something students don't always realize is that their teacher doesn't need 30 copies of a program that prints "Hello, World". You are not "producing code", you are "demonstrating your understanding" of the content.
Autocomplete, autoformatting, auto-anything is harmful for the learning process. If the computer does it for you, then how do I know you know how to do it?
Once you can demonstrate that you know how to format your code properly, then those auto-tools can help you, rather than being a crutch.
Once you know "I can solve this problem by using a substring" you can use autocomplete to figure out the exact syntax for the substr() method. But if you're just looking through the auto-complete method list and clicking on things until one of them works... that's not "knowing how to program".
