As far as the purpose of DNA is to tell the rest of the cell what proteins to synthesize, over 85% percent of our DNA is never translated to protein [1]. But leave alone our knowledge of DNA, biology rarely works in a manner that's best suited for functional efficiency. For examples, look at how the vagus nerve evolved, or look at vestigial organs. The question for the gene is rarely "is this the most efficient way of doing things?" Rather, it is "is this strategy good enough for me (and my descendants) to pass on my genes?"