The huge banknote denominations resulting from Zimbabwe's economic collapse in the late 2000s appeal to a wide audience for different reasons. They can be a fun item, sort of like those novelty one million dollar bills you see as gifts sometimes, except these have real history behind them and were once actually used as currency. They are a reminder of the effects of a corrupt government, and evidence of the results of extreme inflation. They are also interesting collectables.
We also sell other hyperinflated currencies, and other paper money that is cool or interesting.