I especially agree that essay writing is hugely useful. I'd even go as far as saying, the ability to think clearly is fundamental to a happy life.
It didn't explain the goals well enough to parents, and many teachers didn't have the number sense themselves leading to many of the examples are passed around showing how the whole process is broken. There is also a question of if even works well, as it is somewhat akin to teaching someone the shortcut on how to do something before they have mastered the long way of doing it. Many experts in their fields have shortcuts, but they don't teach them directly to juniors in the field as there is value in learning how to do it the long hard way, as often times shortcuts are limited and only an understanding of the full process provides the knowledge of when best to apply different shortcuts.
No, it doesn't. And that's one of the main tragedies in modern discussion about education. A lot of people think that we have to teach the way how experts think. But it doesn't work.
Take a look at programming for example. Everything you ever really need to know about programming, can be described in single A4 probably. But it has no any use if you learn. It even makes things worse, because it's a thing you have to pay attention to, but you don't really understand. You have to learn via small babysteps, automate a lot of small things in your brain, practice a lot etc. There is no shortcuts in learning.
I remember being told the same thing, but I happen to believe that it was a fantastic policy, with a lackluster explanation. The idea that you wouldn't have a calculator was obviously silly, even at the time, but underlying observation that relying on the calculator would rob you of the mental exercise the whole ordeal was supposed to be was accurate. The problem is that you can't explain to a room full of 12 year olds that math is actually beautiful and that the systems principles it imparts fundamentally shape how you view the world.
The same goes for essays. I hated writing essays, and I told myself all sort of weird copes about how I would never need to write an essay. The truth, that I've observed much later, is that structured thinking is exactly what the essay forced me to do. The essay was not a tool to asses my ability in a subject. It was a tool for me to learn. Writing the essay was part of the learning.
I think that's what a lot of this "kids don't need to calculate in their heads" misses. Being able to do the calculation was only ever part of the idea. Learning that you could learn how to do the calculation was at least as important.