For one, it only a subset of Noscript: "A simple extension that brings SOME OF NoScript's functionality to Chrome"

Secondly, in order to achieve its goal, it's relying on a hack:

     ...
     if (getElSrc(this) && getElSrc(this).toLowerCase().substr(0,11) != 'javascript:' && getElSrc(this).toLowerCase().substr(0,17) != 'chrome-extension:')
     ...

Not taking anything away from this extension, just that this illustrates what everyone's saying - concerns about reduced functionality.