I don't get this. It's tethered to the wrist so where's the risk of dropping it like a naked iPhone and shattering the screen? It's IPX7 water resistant (to 1 meter for 30 min) so there's no chance of the usual "accidental" water damage. And why would it be more likely to malfunction beyond the 1 year warranty than other Apple products?
I have always used cases and screen protectors on my iPhones and iPads, so they are decently protected.
Wearing the watch on your wrist may subject to to all sorts of collisions and impact shocks - that is my concern. I have read plenty of accounts of case and screen damage according to posters here.