....and how about the brain power to work out if you've put in the right info to the electronic brain?
Like any computer, if you put cr*p in, you get cr*p out. If you are only trained to punch numbers on a key pad, then how can you catch mistakes before they become a problem?
Children are still taught basic arithmetic like long division, no-one argues that this is unnecessary even with the advent of calculators. Why should student pilots be any different?
Learn the basics first, then look at more efficient/easier ways later once you have the basic principles understood fully.