Perhaps, just perhaps, undermining any interest, even if you undermine interests of others, to an advantage to yourself, turns out to be a disadvantage in the run, long or short.
Neither does it refer to transcendent Sages or Junzi, nor Xiaoren, who forgets friendship for profit and benefits oneself at other people 's cost, but morals of "common people" between them.
But Mr Eichengreen notes that the euro, by militating against more widespread beggar-thy-neighbour policies, may have helped preserve the European single market.
Its significcance is manifested in the individuals' displaying self-benefiting and altruistic spirit when personal benefit is in conformity with that of society or other fellow beings.
For example, almost everyone recognizes (with some exceptions) the elementary moral principle that you should not do something for your own benefit if it harms another person.