Earlier quoted context omitted.
Security updates and significant speed improvements are sufficient reason to upgrade, I'd think. Siri Shortcuts is also a pretty incredible feature if you're a power-user.
Maybe in theory security updates are worth it, but in practice if an update slows down my day-to-day usage that’s a bigger deal than some theoretical security vulnerabilities which I’ve never actually experienced on any iPhone. Especially if we’re talking about non-tech savvy users. So an update better have some compelling reasons to upgrade besides security.
Why the downvote? Is it such heresy to say that many users care more about performance than security? I’m not suggesting that security is unimportant, just that it’s not very compelling if it’s at the expense of performance. For example see all the recent Intel processor exploit patches. Personally I would take an obscure attack vector on my private desktop computer over a ~5% performance loss.