Wholeheartedly agree with this. Right tool for the problem at hand, and sometimes that means using multiple tools (or paradigms). Incidentally, one of the things I like about Python, in that is so easily lets you mix paradigms such as FP & OOP. Certain use cases just don't naturally fit w/ a pure FP style, nor a pure OOP style, but sometimes a healthy mix of both is in order. One of the areas FP really wins is in ease to introducing parallelism. If all of your parallel functions are pure, introducing parallelism should be a non-issue. Results of a function only depend on the (non-global, immutable arguments and, possibly, immutable global state). Shared mutable state is the bane of all parallel programming. Shared mutable state necessitates locking of some form, and even experts get it wrong (and non-experts get it wrong very frequently) - personal experience, no citations.