100% Disagree, If they don't work then how can they become good at it. It is 100% a needed skill for infielders without a doubt! You will not magically be able to do it!
Of course there is a time and place for it that goes without saying. And you contradict yourself in your post! You say its not necessary then you give examples of why it is! And you can set your feet and still take the shorter path of sidearm or up hill throws!