It's highly redundant when there are 2 strands, as is the case with DNA. RNA has a tendency to accumulate mutations quickly, as evidenced by the many hundreds

It's highly redundant when there are 2 strands, as is the case with DNA. RNA has a tendency to accumulate mutations quickly, as evidenced by the many hundreds of variants of SARS-CoV-2 that have already been sequenced (and that's with only ~30,000 bases).