My phone has basically the entire recorded history of human knowledge. It has the ability to communicate instantly with people all over the world. That's a lot!
I own an ecommerce business, and on a typical day I'll check in on sales via the Shopify app, correspond with customers via Gmail and maybe take some photos to post on my business' social media accounts. I also use my phone to call and text my parents, wife and friends. I probably spend at least an hour every day reading news on my phone. And yeah, sometimes I fritter away time on Reddit.
People love to criticize when they see others on their phones in public, but you know what? If I'm sitting somewhere for a few minutes with nothing to do, I can pull it out, fire off a few emails, and then have a few more minutes to pet my dogs when I get home. My dogs deserve those extra minutes. They're very good dogs.
A phone is a multi-functional tool that can be incredibly useful (or also a way to waste a ton of time), and criticizing people for using that tool without any idea of how or why they're using it is silly.