Anis,
The benefit is for those that want to script MoI. If you dont want to script MoI then it wont be of interest to you.

You've seen Michael write scripts for people to do special things or automate a process. This documentation will be for those that want to figure out and write things for there own purposes or other people.

So even if you dont know javascript, eventually there will probably be quite a gathering of specialized scripts that one could browse and choose from.

If I became very good at it, I could even take requests and write custom plugins for MoI and charge money for them!