Apple just seems to be in a rush to launch half-baked features then keeps them in a weird state of stasis for years. The globe/FN key changes the keyboard layout when tapped, which is very useful since I type in multiple languages, but after a few dozen uses it simply... stops functioning. It's been broken for years. The only way I've found to fix it is to open the command line and killall Dock and killall Finder. But then language switching fails again a few more switches later. Not fixing a feature that has a whole key dedicated to it just shows how careless they've become.