Because they’re only little once.
Fast forward to 2050, and your child is now a parent, and you’re a Grandma (OMG)!
Your grandchild loves watching the film you made in 2019, and seeing her Mom getting thrown in the air by Grandpa. And because she has no filter, says “Grandma, your face used to be so smooth!” and giggles, “Uncle used to sound like a girl!!”
This film will become one of your family heirlooms and get more valuable with time.