There are plenty of resources on why you would want to program functionally. One of the most notable one is: http://www.cs.utexas.edu/~shmat/courses/cs345/why

There are plenty of resources on why you would want to program functionally. One of the most notable one is: http://www.cs.utexas.edu/~shmat/courses/cs345/whyfp.pdf http://www.cs.utexas.edu/~shmat/courses/cs345/whyfp.pdf Benefits include: Easier reasoning about code correctness. More powerful abstractions leading to clearer and more succint code. Easier mechanical refactoring of code. Easier parallelism. More powerful compiler optimizations.