I used my iPhone X un-cased for nearly two years based on that reasoning. My replacement is cased.
And I've realized: regardless of how thick the phone is, people are likely to drop them, and give the materials nature of these things, a case is going to be required. So I'd rather start with something as thin as possible, given that I'm going to add a case either way. The end result is therefore as thin as possible.
Because you can't buy something for a thick phone to make it thinner. Each person can make their own decision on the thickness/other concerns trade-off.
Because the thinness is a design decision unilaterally made for you and whose potential downside comes at your expense.
I always get thick, rubberized cases. The high friction makes phones easy to hold, and they've never been damaged from drops (like I'm sure OEMs, especially Apple, would like for repair/replacement $$$). :3
Because you can put a decent case on a thin phone and get a reasonably sized brick that can fit in a pocket and doesn't feel too awkward to hold in your hand. When you put a case on a not-so thin phone, it becomes way to large for most people.
