The big difference is the loss of non verbal communication such as body language, pauses, etc. I agree with the author that there’s an important element of presence in your current surroundings that is lost with the proliferation of smartphones.
The loss of non verbal communication was also a thing in epistolary communication, a common practice for all social classes (even those who couldn't read or write would manage to get letters or postcards written for them); and that was considered a cultivated social activity, not at all dehumanizing either.
It’s amazing most people have no clue that they are mapping their mood state onto their own interpretation of someone’s text messages. We evolved to read non-verbal communication.
Key and Peele have a great skit on this: https://www.youtube.com/watch?v=naleynXS7yo