The flat sides are a good point, my favorite iPhone was the 4S, which definitely felt a lot more stable in the hand without a case than the rounded-side models (I'm currently still using iPhone X—with a grippy silicone case, but looking to upgrade soon). But then the newer phones are much larger and heavier than that phone too, and as I understand it, much more expensive to repair (for example ~$550 for iPhone 14 cracked rear glass). Since I tend to keep phones longer than 2 years these days, AppleCare will run out. I'm hoping they'll start to make the Pros with non-glass backs again, that'll give me more confidence.