I don't think that supporting or adopting bitcoins has anything to do with some countries credit rating. These are two different categories. Availability to do business with bitcoin still doesn't affect the credit rating and I don't think it ever will. Maybe if some day there will be separate bitcoin credit rating.
Yes it does.
...more people borrow money to buy bitcoins and the AAA credit rating allows them to buy more. They can either waste the money on worthless junk or they can buy bitcoins and secure their future.
...Jokes aside, the credit rating will influence the fiat system, because investors use that as a indicator to decide if a countries financial system is sound enough to invest. If the fiat system is suffering,
then investors look for alternative investments in Safe havens, and we all know some of them are already looking at Bitcoin as a Safe haven,
when things start to slide in the fiat system. { Example : Greece & Venezuela }
