In answer to the thread topic, yes, you sure can.
This entirely depends on the person. A smartphone is merely another tool, among other things-- if their quality of thinking was limited before, it will certainly be limited after, while the reverse is also true. There are many people who use them as tools for practical information and teaching, as well as for social reasons, gaming, media, enterprise, reading, and many others.
If anything, it just enables a given behavior, but I don’t believe it modifies anything that wasn’t already in place. By extension, it doesn’t mean that if the person didn’t have a smartphone, that they’d be doing something more “productive” or “worthy of their time”.
Communication and social interactions evolve. The same was said about print/books, cinema/movies, email, etc. and now smartphones, but they all have their pros and cons. Social relationships have and always will change, as a given. I think it’s narrow to judge in a vacuum, as there is certainly more depth to why the technology has been adopted so broadly and at this rapid pace.
I think with most people who object to it, they haven’t found many reasons to integrate such tech. into their lives, which isn’t surprising. They don’t have a real grasp of how it works or how it can benefit them, aside from their basic level of interest (be that an occasional email here or there, or sharing photos with the family). It’s mainly a lack of perspective, but with that, many people are content/comfortable with their lives, and don’t actively search for reasons to do things any differently, if they currently work. That’s fine, but what it means is that they typically overlook any other associated benefits, or assume its excess or even damaging when others do.
I think balance is the key, ultimately-- some people function better or worse with such devices. Personally, I’m curious, love technology, and actively find ways to integrate it into my life, along with readily sharing it with others who are interested. I haven’t had one person complain that their life wasn’t better off because of it. I’ve met and maintained many friendships because of it, and I’m 100% positive we, as a society, will continue to progress with more technology in mind, not backwards-- so in a sense, there is no real incentive to downgrade or ignore it, other than for personal reasons/objection (which I personally think it’s fine, once it’s not a knee-jerk reaction).
If I find my life has swung too far one way, then it’s upon me to swing it the other (moderation)…not just with technology, but with anything.