That’s genuinely one of the things people look for; iPhones are incredibly dense designs, in a very sleek, smooth, light package, and people love them. A very basic phone case and a screen saver adds nearly half the OE thickness of the phone to the package, and look how many people forgo those, even on a phone that’s $1500. If I added that much thickness to a phone that started out at .5" thick, it would end up feeling like I was carrying a brick on my pocket all the time.
I would still take the brick with replaceable battery though.