Some people has seen me using Planck Keyboard.
In fact, I've 3 of them. The keyboard form factor is called "40%" which has only 4 rows and does not have function row or number row.
To type them you'll need more modifier keys to trigger the additional layers. They're called
Raise layers. When you press
Lower modifier key with
Q you'll get
Raise + Q you'll get
1, for instance.
They need more keystrokes but less finger travel.
The first Planck I had was the Rev. 3, which is also the first custom mechanical keyboard I had built. Apart from the bizarre and hard-to-master layout, I found that it was using QMK Firmware, the most powerful keyboard firmware which you can customize & program the firmware however you like using code.
I've built the SuperDuper Mode which was heavily inspired from this and this. The idea is I can ditch all the arrow keys and use only keys on the home row for movements in all directions. It was the time when the old version of Karabiner is not yet compatible with simultaneous keypress in macOS Sierra, so I have to move my SD mode to physical keyboard like the Planck.
I saw someone stated that 40% keyboards are the Dark Souls of keyboards. It takes time to learn to use, but once you've mastered it, then you can use all types of keyboards easily.