Actually, that's an interesting question. Having built similar systems before, the main reason why you would not simply run a function every time your input is

Actually, that's an interesting question. Having built similar systems before, the main reason why you would not simply run a function every time your input is updated is that you often need for your computations to keep a certain amount of state, which may depend on the input. However, as Incremental does not seem to support much in the way of stateful computations, I'm a bit puzzled wrt to what problem it addresses.