As a parent, I rarely have time in chunks larger than a few minutes before being interrupted by children needing a drink, drawing on the wall with permanent marker, or escaping the house and running toward the road. It's not just about how much time we have, but how it is discretized. Not doing social media for some people equates to having several 5 minute chunks of time throughout the day doing nothing instead of doing something. Maybe they would be better off just meditating, but reading books this way doesn't really work for me at least.