Debtors have to sell the local currency to acquire dollars so they can pay their debts. This can become a death spiral for the local economy. If good information about what was going on in these countries had been available, many of these loans would not have been made. Honest Asian businesses would not be ravaged by declining exchange rates and rising interest rates, and the world would not have to fear further collapse in Asia. There is a systemic fault here, because the mixture of bank loans and portfolio investments on which the Asian countries have relied to fund their economic development is inherently unstable.
Banks accumulate information and keep it for their own exclusive use.
Secrecy makes sense for banks, especially in an environment where an ever-increasing fraction of their earnings comes from trading, and the habits of secrecy hang on. Markets, by contrast, cannot survive without transparency. Markets are an inherently less expensive way to price and raise capital, in part because they use generally available information. Banks themselves, once funded from public deposits, now rely on markets to provide most of their lendable resources. Companies get access to capital markets when they grow large enough that information about them is widespread.