Generally, RMB plus USD, EUR or JPY. The advantage of all-currency card is that it can exempt 1.5% currency conversion fee.
For example, if you use a dual-currency card of RMB and USD, and pay with Thai baht in Thailand, you will incur a currency conversion fee of 1.5% (of course, if you pay with USD or RMB, you will not incur this fee).
All-currency cards will not generate such fees.