I don't get it, there's no choice between everything being essential and lots of the genome being junk. Redundancy mechanisms like multiple copies of genes, whi

I don't get it, there's no choice between everything being essential and lots of the genome being junk. Redundancy mechanisms like multiple copies of genes, which we know is there, reduces the risk of harm from mutations. Why can't most of the stuff in the genome have the label "useful, but we have backups", rather than "essential" or "junk"?