It allows smart contracts to use real world data. A silly example. Lets say you have a vending machine selling sun screen where the pricing is dynamically chang

It allows smart contracts to use real world data. A silly example. Lets say you have a vending machine selling sun screen where the pricing is dynamically changed based on the weather, if weather data is available to the smart contract then this can work perpetually without human intervention. Or at least until the machine needs to be serviced :P The API is unlikely to disappear because the smart contract automatically pays for using the data.