I'm a Software Engineer and I've never downloaded or used an "app" on a smartphone.
I did buy a new Android one for $20USD in Guinea, but I just use it to tether my laptop and it doesn't have a single app on it. I've never browsed the web on it or made a phone call because the interface sucks.
It's interesting to watch how addicted people are to their phones, and how much it invades everyday life. I think I have an interesting perspective looking from the outside in.
Whenever I'm out for drinks or dinner, every single other person checks their phone about every 1-2 minutes, often spending at least that long doing nothing other than staring at their phone, oblivious to those around them. During those times I really enjoy looking around to see who else isn't on their phone, and I make eye contact and smile to see what kind of human responses I can get. I have previously been at a table of 10 people and I'm the only one not staring at a phone.
I get that they can make life much easier in certain situations (coordinating meetups with people, locations, timing, etc.), but to be honest the more I observe from the "outside", the more I'm convinced the negatives outweigh the positives.
Of course everyone needs to make their own choice, and I'm by no means saying everyone should ditch their phone or that phones are stupid.