This is like saying "the benefits of functional programming are overstated". If you are happy with mutable collections, you've happy with mutable variables, per

This is like saying "the benefits of functional programming are overstated". If you are happy with mutable collections, you've happy with mutable variables, pervasive side effects and essentially the status quo. Many of us are not happy with the level of software quality out there and the status quo, Rich Hickey included.