It's in moments of boredom that you start having deep thoughts about the world, start thinking through solutions to problems you have, start thinking about changes you can make in your life.
I got rid of my smartphone and now the 20 minutes each day on the train where I'm "bored" are one of the most valuable parts of my day. And my mind feels much fresher after it, rather than being crammed with 20 minutes worth of mental junk food from the internet.