Well, apparently they were back then and still are today for people of all ages.
My kids turn into saints once they see the coloring sheets rolling out of the printer. They love it when I start passing out coloring printables with their favorite characters on it. The most valuable aspect of coloring pages are there educational value. They will help your kids with their motor skills i.e. finger dexterity, eye-hand coordination as well as increase their mental capacity. The list goes on regarding the benefits of allowing your child to color versus playing video games or watching television.
In fact when the internet came initially people were less aware about its utility but now parents can get their kids wonderful growing opportunities. It can either be downloaded or can be used over monitor itself.