Not to US who would obstruct World Bank or IMF financing infrastucture that advances the interests of Iran. An obvious way to export oil and natural gas from the countries to the North of Iran would be by pipeline through Iran, but the US insisted they must go through Afghanistan. That's also why they want to keep their forces in that country.I don't understand your question.
Put simply, this bank would mean that poor countries now have an alternative to get their funds from apart from established international organizations.
Having another choice is always a good thing, no?