https://symboliclogic.io/years-of-pain-solved-by-really-obvi...
It requires an tray app called Karabiner Elements to link the function keys across keyboards.
Though, when someone says "I don't want a keyboard with layers", it's obtuse to say "you don't want the shift key?!".
Many things in tech are trade-offs. There are big benefits which come with using layering, but there are also some downsides.
It's entirely reasonable for someone to prefer a more traditional keyboard layout, over a more niche keyboard layout which would take some time to get used to.
It’s not obtuse to frame “layers” into something the person is probably already familiar with. Even if they still end up disliking layers (that’s fine!) it helps bridge the gap on different keyboard layouts.
Besides reducing the number of keys, are layers good for anything else? Are there any websites with layers designed for specific editors, etc?
I use several different machines regularly (mix of Windows, MacOS, and Linux) and it is great to just have my custom stuff with me at all times. Macros are the only thing that is OS specific.
The most significant advantage, IMO, is allowing for reduced hand movement. -- e.g. enabling access to cursor keys or a number pad without needing to move your hand.
To an extent, layers also allow reducing usage of the (weak) pinky fingers in favour of the other fingers.
I have "move to previous virtual desktop", "move to next virtual desktop" with convenient key-chords; but these could be put on a layer as well.
I think "layers for specific editors" is unlikely. These split keyboards are great for "both hands on keyboard" tasks, but much harder for "mouse + keyboard" programs with QWERTY-specific keybindings, like Blender or whatever CAD.
The reduced number of keys has some benefits: the keyboard takes up much less desk space. With the DIY keyboards it allows for a lower cost: smaller number of keys also allows for a smaller PCB, and not needing to order as many key switches.