I use my everyday phone (an iPhone 11) with either the Cyclemeter or Ride with GPS app to track my ride (I use RwGPS particularly if I'm following an existing route). I do have it paired with a chest-strap heart-rate monitor, and could pair it with a rotation counter or power meter, so in terms of data collection, there's no advantage either way (except that with my phone, I am either restricted to Bluetooth gadgets, or need to add a Bluetooth/ANT+ gateway). In terms of data display, the dedicated head units have an advantage (which is a pet peeve I have with the apps, since there's no reason they couldn't offer customization the way Garmins do). For the most part, I ride with the screen off, and have the app announce my stats at regular intervals. If I do need to look at the screen momentarily, it's not hard: the screen is oriented so it can see my face, and face-unlocking means I just need to swipe up on the screen. Battery life is a non-issue* even on 150-mile rides; power banks are an easy insurance policy. The phone is water-resistant* and has lived on my handlebars through some pretty heavy rainstorms. I do have a case with a lanyard loop in the event my bar mount (Quadlock, recommended) fails, but so far so good.
I did consider getting a dedicated head unit, but I've read numerous complaints about how buggy Garmins are especially, and just didn't see a big advantage over my current setup. For me, "new toy to play with" is at least counterbalanced by "new gadget that needs managing."
There are times when its nice to have the phone accessible on my bars, apart from using it as a bike computer. The only time I've cracked the screen on a phone was when I dropped it pulling it out of my back pocket on a ride (while stopped). So the "wear-and-tear" argument could go either way.
* The one caveat about battery life and water resistance is this: the phone is smart enough to deactivate its charging port when it's wet. On a very rainy 145-mile ride, I was worried that I wouldn't be able to charge it to have enough power for the next day's ride, and I was depending on it for navigation. In theory, one could use wireless charging as a workaround for this, but I didn't have a wireless charger on that ride.