I’ve done some research into this myself and thought I might add CONCURRENCY to the list of reasons to use a functional language. See at some point in the near future processor speed will not be able to increase using the same cpu technology. The physics of the architecture won’t allow it.
So that is where concurrent processing comes in.
Unfortunately most OOP languages cannot take advantage of multiple processors at once because of the interdependencies between data.
In pure functional programming languages the computer can run two (or many more) functions at once because those functions are not altering outside state information.
Here is an excellent article on functional programming you may enjoy.