In declarative systems, you want to explain the final end-state. Often your requirements on the final end-state involve some predicate logic. I want (A and B)

In declarative systems, you want to explain the final end-state. Often your requirements on the final end-state involve some predicate logic. I want (A and B) or C. Using an Or makes sense, if you want your declarative logic to work on both windows and linux. Or you want configurable declarative logic, or you want to be easily able to manually change the files. A very natural way to do predicate logic is "if A is true, then B should be true". That is logically equivalent to "B or not A". But letting people write "if A, then B" is just nicer. Hence declarative logic is much nicer with "if statements". Perhaps another way to view this is that many declarative systems "build" their description of the desired end-state imperatively. I wouldn't say that applies here, but I could imagine cases where you want to say 'for all elements here' which might be best solved with a for loop.