well I think the US just thought it would be too inconvenient for countries to trade outside the US dollar.
But after what countries are seeing the US do to poor countries by using the US dollar as a weapon to sanction countries, and then hold a coup, these countries obviously want out of this system and opted for trading in local currencies with BRICS, instead of US reserve.
It is far more inconvenient for these countries to be sanctioned by the USA, than to switch trading economy, hence the mass move away from the US dollar reserve.
US reserve currency is what the US has abused to sanction countries it wants to coup or steal from.
Now that countries on BRICS do not need the US reserve currency anymore it's weakened the US and will continue to do so as more countries join BRICS and the US reserve becomes irrelevant.
what you and the West failed to realise due to complacency, is that many countries are moving away from being reliant on the US reserve and becoming wealthier and free from sanctions and threats. US is losing its biggest weapon 😂😂
BRICS is the safe option for countries that the US can threaten with sanctions, as it has got away with for decades.