[Dunearhp]

It is one of the few arguments that doesn't first require the other person to have a deep understanding of functional programming.

Try to convince someone of the value of immutability without mentioning concurrency.

Imperative and functional programming relate in the same way that arithmetic and algebra relate. It is hard to do deep reasoning in maths without algebra and it is impossible to evaluate the value of most algebraic expressions without arithmetic.

There is a reason that functional programming is at the forefront of concurrency research. In the long run, imperative only approaches will be unable to compete, and functional only approaches will remain on paper.