What's a First Strike worth and why bother?

Did anyone see the article that the US Mint published concerning the First Strike Designation on the the 2006 gold buffalo and silver and gold eagles. They indicate they do not take inventory on when these coins were struck only packaged and therefore they do not designate any as first strike. In other words coins delivered after the thirty days may have been struck within the first thirty days. In fact a lot probably were as the acticle indicates that for proof coins about 50% are struck before the first issuance date.