Turn by turn directions and map overview for point to point navigation work if I have a signal when I enter it. If I go exploring back roads in the country on my motorcycle and drive for several hours and then want the nav to show me the shortest route home, I am SOL without a cell signal.
Certainly not a problem that most users would have, but in my case having the dedicated nav device is well worth it.
I think your experience there is accurate. For city navigation especially, the smart phone based nav is head and shoulders above pretty much all the dedicated nav devices. More current maps and info on points of interest to just name a couple. If I only used nav in cities in the US, I would no longer own a dedicated nav device. It just happens that for exploring far away from urban centers a dedicated nav is more reliable in my experience.
And no $25 extra bucks a month on your cell phone bill for all that connectivity. I don’t remember what model I have, but I’ve never had a bit of trouble with it. I bought my mom one for her car a few years ago after comparing the TomTom and a few other brands.
For the money, for comparable models, the Garmin had the most user-friendly interface and the biggest easiest to see screen. And it’s pretty darned accurate and often gets better satellite coverage than the survey grade Trimble we use for field jobs.
When the Trimble balks, our buddy “Jill” (my Garmin) can always get a lock and she’s pretty darned accurate too. I haven’t upgraded maps for awhile, but I do remember their website as being well…not super intuitive. It did take a little more work than other websites, (and not as much as some), but once I figured it out it was fine.