I cringe when I see number pads with a 1u 0 under the 2, as seen in most 1800s, 96%, and some other compact 100%-ish layouts.
(Cherry G80-1800 and Keychron K4)
I have to think that people who like those layouts do not actually use the 10-key correctly. The 0 key is for the thumb! When 0 is a 1u under the 2, you are forced to use your middle finger or else
shift your wrist in order to use your thumb. I suppose you
could reach it with your thumb without moving your hand, but you would have to contort your thumb to do it because there is usually an arrow key in the way. Whichever way you do it, hitting a 1u under the 2 is either slow or not ergonomic.
I am fine with layouts where there is a 1u 0 under the 1 and a 1u 00 under the 2. It's not my preference, but
for the special case of accounting data entry, the 00 key under the 2 can improve efficiency despite the aforementioned difficulties.
I do like compact full-size boards, but I believe a 1u 0 under the 2 is the wrong compromise to make. For me, the ideal compact full-size layout would be more like a 75% with a normal number pad added on so that the right arrow does not encroach on the numpad 0. The DriftMechanics Austin layout is a good example, and even more compact layouts are possible.
For comparison, behold the beauty of this Sharp 10-key calculator and its wide well-positioned 0 key: