It is correct that IOU's can be abused, like many other things.

However, it is foolish to deny their positive use as instruments of credit facilitating division of labour in modern economies.

Credit in real goods is what powers capitalistic production and supply chains for consumers' real world lives. We cannot eat bitcoin. Or gold for that matter.

On 'cheating': Cheating banks and trusting fools will always be punished, usually within a few years of less. Honest banks persisted in the past for hundreds of years. Only the government has the power to cheat unpunished and force their 'licensed' (enslaved) banks to cheat through regulation.