[mrkeen]

> Who is "we", what was the price, and what was the imagined reward?

Slow down and re-read.

>> You get: the knowledge that your function's output will only depend on its input.

>> You pay: you gotta stop using those for-loops and [i]ndexes, and start using maps, folds, filters etc.

[troupo]

Still makes no sense. Once again: who paid, what was the price, what was the expected reward?

[tmtvl]

Who paid: programmers switching to FP.

What was the price: two things:

- The programmers must stop using for-loops and [i]ndexes.

- The programmers must start using maps/folds/filters/et cetera.

What was the expected reward: the knowledge that their functions' outputs will only depend on their inputs.

In short: programmers who change their behaviour get the benefit of certainty about specific properties of their programs.