Sounds like you've already gotten enough nudges to take the leap, but I'll add one more (with a few caveats) to the pile. I had a smartphone for about a year and a half, until it crapped out on me right in the middle zone between the warranty expiring and my next free upgrade. (I'm still with Sprint because I'm part of my mom's family plan where we are somehow grandfathered into a pretty competitive price, and I've been too lazy to figure out switching for the minimal savings it would get me.)
Rather than shell out for repairs or a new phone I had them transfer my service back to my old flip phone "temporarily" until I could upgrade again for free. I still haven't upgraded back to a smartphone, and it's probably been a couple years now. I almost never miss it. The caveats (some of which maybe don't apply to you if the more current dumbphones have better compatibility in some areas):
-Nobody I know makes phone calls very often anymore, instead they send super long texts, which for me either don't come through, come through blank, or come through broken up into smaller chunks, often out of order.
-responding to said super long texts without a qwerty keyboard gets a bit painful on the thumbs
-Picture mails come through sporadically, if at all. Can't seem to send them anymore either.
-Conversation style texts, the kind sent to multiple recipients, also don't come through. Unfortunately this is the primary way some of my closest friends get in touch, make announcements, or send updates (recent example: best friend was in labor literally down the street from me, it was longish and complicated and I was on the edge of my seat waiting for individually sent forwarded updates through another friend who lives across the country since the dad-to-be only had time to send out messages group-style, which my phone wasn't showing me.)
Those are the only differences I've noticed that might actually make me consider upgrading again if I could find a smartphone that actually fits in my hand instead of the behemoths they all are now. But like I say some may have more to do with the fact that my phone is now probably about 6 years old rather than the fact that it's not a mini-computer. Good luck if you make the switch! You'll be surprised both at how little you miss the apps once you break the initial addiction, and at suddenly noticing how much time everyone else spends on theirs.