Why? right up until about 100 years ago it was very common for people to wear lockets or other jewellery with hair of their deceased (or living for that matter) loved ones.
When I was a child the first tooth I lost was made into a necklace by my grandmother - my mother still has it somewhere.
Sometimes (although not so often) today a guy or a girl still asks for a lock of their beloved’s hair. I have a lock of hair from my dearly-loved godson.
Having physical reminders around of your loved ones, whether living or dead, is a great comfort and help for some people. If you don’t find it so, then you don’t need to see 'em, but don’t criticise!