FB Profile Picture

How come if your profile picture is the same for long time, Facebook tells you maybe it’s time to change it. After the age of 6 I kind of grasp the notion of time passing by and not sure I need a responsible adult to remind me of it. Do they want to make sure people are not in denial of their age? Why rub salt into the wound? Or is it just another reason to have traffic on the network? I am planning of keeping the same profile picture until the age of 84. Then I will ask someone to replace it with a picture of my grave.