This reminds me of the NeXT ADB keyboard that has 'Command' as a bar under the spacebar[1]. I appreciate the utility of remapping 'space' as a layer switch, but I would prefer not to have to unlearn 40 years of spacebar usage. I could see enjoying implementing this on a separate key that I can still whack with my thumb-- just not a key that falls within the standard ANSI PC layout.
1. https://deskthority.net/wiki/images/8/87/NeXT_ADB_keyboard.j...