Perf, though? If a perf optimization changes the UI noticeably other than by making it smoother or otherwise less janky, someone is lying to someone about what "performance" means. Likely though that be, we needn't embarrass ourselves by following the sad example.
No, UIs churn because when they get good and stay that way, PMs start worrying no one will remember what they're for. Cf. 90% of UI changes in iOS since about version 12.
I thought languages such as Rust and flamegraphs and etc were supposed to help us avoid doing all this testing and optimization right? Like I use the built in analysis tools that come with cargo and such and what I have on my os, tools like cutter or reverse engineering tools. Even on python I use the default or standard profiling and optimization tools, I wonder sometimes if I am not doing something enough if the default tools thats recommended should cover most edge cases and performance cases right?
And software ultimately fails at perfect composability. So if you add code that purports to be an optimization then that code most likely makes it harder to add other optimizations.
No, UIs churn because when they get good and stay that way, PMs start worrying no one will remember what they're for. Cf. 90% of UI changes in iOS since about version 12.