There are benefits of engaging our brains over having to depend entirely on technology. I know it sounds weird, but it is much more valuable to number crunch with pen and paper than to use a calculator.
There is essentially nothing wrong with a calculator. It is designed to help us get answers quickly. However, the person who is number crunching is growing the brain muscle more as compared to the one heavily relying on the calculator.
In our day and age, we are abdicating the use of our brains and are overly dependent on technology. It's a silent epidemic. Listen to this.