I will only add to your confidence if things go a little wrong or you read the weather badly.
In terms of what it does for you, very little. IT should not be used for bad weather flying if you intend to fly in IMC conditions get the IR. The IMC was only ever designed as a " get out of jail free" in those rare occasions we screw up.
If your going the whole hog, save the dual time and just do usefull hour building trips and exercises instead.
I did multiple cross countries and many flights on basic nav exercises doing practice diversions etc, that will probably help you more.
Visit different airfields etc and get more varied experience.
I did modular and I did the IMC, the later was a waste of time.
Hope that helps