'Useless specks of dust' turn out to be building blocks of vertebrate genomes
Maybe we should use the word "use unknown" instead of "useless" when dealing with things we don't fully understand.History has humbled us countless times. I recall a recent Veritasium video wherein famous mathematicians of centuries past labelled the concept of negative numbers "useless" (because they didn't understand how they could be useful). My high school bio teacher confidently claimed that the appendix was a "useless organ".