DNA barcoding
One good thing about DNA barcoding is that it helps human beings get around ideas that seem right but are really wrong.  For example, some animals look similar even though they are not closely related.  Some animals look different even though they are closely related.  It is easy for a scientist to think two species are related because they look or act alike.  For example, cows are more closely related to whales and orcas than they are to horses, even though cows walk on hooves, live on land, and eat grass like horses do.  Looking at DNA barcoding makes it easier to see what really happened in evolution.