Calculators can do for you. But if you have no calculator, what are you going to do? We should learn and we should be ready to do it on our own if a need arises. Otherwise, you will face problems. How to calculate the standard deviation will be taught to the students during their high school studies. We used to solve these problems during our SSC and Intermediate, Those days calculators were not available. We used to use logarithm books. These days students will never know about these logarithm books. They will carry scientific calculators and get all the problems done using that.
We should not completely depend on instruments and tools. They tend to give problems sometimes and we may not be able to understand how to solve our problems. So one should always learn these statistical problems and be ready for doing without a calculator also.