The reason something like this scares me is that it lulls users into a higher level of trust... and doesn't protect them from hacked sites, or sites that choose not to implement this.
This mechanism isn't intended for users -- this is a tool for site authors, to cooperate with them in enforcing their policies. The site still has to make a best effort at implementing those policies themselves to protect all their visitors using browsers that don't support CSP (which includes every officially released version of Firefox to date). This is an extra layer of protection for users of CSP-compliant browsers, and a benefit to the site through the reporting function.
Please do continue running NoScript if you like. CSP is a mechanism for site authors to declare their policy, add-ons like NoScript and AdBlock are tools for users to declare their policies.