The traditional tiny keyboard is optimized for ease of onboarding, but it sucks to actually type on with any speed. The thing posted has a steeper learning curve, but can be used to type quickly and without even having to glance at the actual keyboard. You can keep it at the back of your phone, or in the pocket of your coat, or have it mounted on the handlebars of your bike. (Actually you can have all three, connecting via Bluetooth.)
AFAIK this is the kind of keyboard military pilots use to quickly type things; you don't have room for a QWERTY keyboard in a jet fighter cockpit.
What I badly miss on the example layout is navigation and manipulation keys. Semicolon + D and semicolon + K have ample room to put there left and right arrows, ctrl + left and right arrows (word navigation), home, end. Somewhere else should be select mode (maybe while holding A), so that the arrows had the shift modifier (selecting) and copy and paste commands (sending ctrl+C and ctrl+V).
OTOH navigation and editing is a separate enough activity to warrant traditional layer switching aka modal editing.
Morse code beats all of these. Steepest learning curve, but fastest entry. At one point I remember people talking about modifying dumb phones (pre iPhone era) to have the ability to enter Morse code via a hardware button on the side of the phone.
The world would be such a different place if Morse code was taught in schools alongside other basics we learn.
If all you care about is typing a stream of letters and numbers, this is indeed so.
But I very often need editing things, moving text around, selecting, altering words, copying and pasting. I need upper case and lower case, fancy punctuation characters, etc.
Not that a proper Morse code mode can't be invented for that: vi gives us an example of such an interface, based entirely on letters and mode-switching.
BTW Morse code is relatively slow to enter by fingers alone, the muscles are too weak for the mass. A proper entry key is fast because it uses muscles of the entire arm.
AFAIK this is the kind of keyboard military pilots use to quickly type things; you don't have room for a QWERTY keyboard in a jet fighter cockpit.
What I badly miss on the example layout is navigation and manipulation keys. Semicolon + D and semicolon + K have ample room to put there left and right arrows, ctrl + left and right arrows (word navigation), home, end. Somewhere else should be select mode (maybe while holding A), so that the arrows had the shift modifier (selecting) and copy and paste commands (sending ctrl+C and ctrl+V).
OTOH navigation and editing is a separate enough activity to warrant traditional layer switching aka modal editing.