The only way i'd see loans or credit working is if you just get the loan in your national currency and exchange the money as needed and spend the bitcoin right at the moment.
Thoughts?
Well, currently there are no Bitcoin loans available, anyway. And I expext that to be the case as long as fiat money remains dominant. Who in his right mind would take a loan in a currency that can increase it's value tenfold over night? Once Bitcoin is widely adopted and 1 BTC is a Kilo of Gold this will change. A smooth 5% Deflation a year caused by growth of the Bitcoin economy will not prevent short term loans just as a OD interest of nearly 20% doesn't prevent people from using OD.
I am wondering about large, long term loans like mortgages, though. At 5% Deflation, everyone would delay buying a house because sitting on your saved bitcoins and paying rent is more rational. If there are no buyer because Bitcoin mortgages are too expensive, house prices must deflate much faster than the rest of the market.
So if Bitcoin really starts to displace fiat money, it's time to sell the house and buy it back when Bitcoin is the only game in town.
-Anu