The TRUST of paper money lays in the CONFIDENCE of EACH INDIVIDUAL.
Money is the LIFE SAVINGS of all Humankind. Some are thrifty, & some extravagant. Money is just a piece of paper, but ULTIMATELY, that piece of paper will HAVE to be able to be EXCHANGED for goods & services to LIVE LIFE & it MUST BE STABLE, & DEFENDED by force of arms if necessary to ensure PEACE & STABILITY, that SAVING INTERESTS are guaranteed for each new note printed, backed by National assets & Will.
Some trust in gold but in the end, NONE can eat gold. The more gold one attempts to save, it will NOT feed oneself or loved ones, as the more gold one has in an UNSTABLE situation such as wars & strife, the MORE OTHERS will demand MORE, eg - one's ENTIRE horde of gold for just a glass of water to survive....
In our World, BRICS nations had the fortune to ride on STABILITY by the US dollar, whom invades NONE but only to DEFEND Peace & stability to ALL nations, often at the expense of their & like minded nations treasury to keep our World safe & stable.
Unfortunately, BRICS nations are poorly managed, heck - even China, the leader, cannot even ensure that their own citizens deposits are guaranteed, let alone war strained RUS. How more the other nations?
Savings are one's own thrift. And it will need TRUST to ensure that such savings are protected. Can BRICS nations guarantee such, not their trust in them with their life savings that WILL NOT go up in smoke the next day?.......Each Human has Free Will, thus choose wisely.....