Noscript doesn't turn off Javascript. Most browsers already have an option for that. What Noscript does is to make the control of Javascript (and Flash) much more fine grained and convenient.
Some typical case:
1. Scripts on poor web sites just serve to detract from the content. Those you simply never turn on.
2. Scripts on good web sites improve access to content. Those sites you enable permanently first time you visit (press no Noscript button in the lower right corner, and select "enable permanently") and forget about it.
3. Some web sites contain a mix of the two. Here you can either explicitly enable a specific object (by clicking on a placeholder, like with flashblock), or temporarily enable scripts for that site.
Basically, Noscript makes more, not less, of the web accessible. The good web sites you use normally will not be affected (as they all will be allowed to run scripts). But following links from social web sites like /. become a much more pleasant experience.
Of course, most of the noise scripts distacting from content are ads, so AdBlock gives you much of the same benefit. But I don't want to hide ads, as that is how the sites pay their bills.