Salesforce Multi-Currency feature is useful for an international organization where different currencies can be made available in one single organisation.
Note: Once this is enabled, it cannot be turned off
Below is an example of how WDCi as a company uses multi-currency:
WDCi HQ in Australia uses AUD
WDCi Branch in Malaysia uses MYR
So how does multi-currency work?
Multi-currency will automatically choose and display the currency based on the user’s personal information. ( User Name | Setup | Personal Information)
When the currency is defined in the user’s personal information, Related objects will inherit the currency. For example, Account, Contacts, Opportunity or even products will be using MYR – Malaysian Ringgit.