There are different types of complexity. Whilst it's easy to see what a simple line of code is doing, it's not necessarily easy to see why it's being done, or

There are different types of complexity. Whilst it's easy to see what a simple line of code is doing, it's not necessarily easy to see why it's being done, or to understand how a codebase made of simple lines works. An extreme example of this is machine code, where every instruction is incredibly simple, but trying to work out what the whole thing's doing in order to debug it can be very hard. As a mere mortal, I appreciate monads and the simplicity they bring to my code.