It's interesting that we're so used to the GUI buttons having that specific behavior of only triggering when releasing, even if you exit and enter the button area while holding the mouse button down, etc.
IRL 99%+ of buttons work by just doing the thing as soon as you press them. But a button that works like that in a GUI would feel wrong.
> But a button that works like that in a GUI would feel wrong.
No, it doesn't. It feels way more responsive.
My pet peeve is "stopwatch apps" which trigger on release instead of on press. When timing something where fractions of a second matter, most people won't realize that it triggers on release and tap down when they want to start / stop, adding some arbitrary delay until they actually release the button.