The infographic shows the 10 most popular banknotes worldwide with its anti-counterfeiting security.
There are thousands of million dollars counterfeit circulating worldwide. Just in The US the FED said 7.3 We conclude that the total value of counterfeits in circulation at any moment is approximately $70 million or about one note in 10,000, and is highly unlikely to exceed
$200 million, or about 2.5 in 10,000.

it's costly for the society (more regulations, more resources to deter, individual or business accepting it accidentally >direct loss,...) Counterfeit money exists since the Ancient Rome at least, and it can destroy a government and its economy. Even the Nazis were counterfeiting the USD and GBP (Operation Bernhard) If only 1% of your circulating currency is fake your government is out. It can't borrow money anymore, business will stop to accept the currency, and since it's the only one, then the economy will be dead.

Do you know how many Bitcoin has ever been counterfeited since10 years? ZERO !