[Palomides]

it's a 'common' (I've at least seen it used in various open-source keyboard firmwares) trick to only debounce the key release; if you think about it, there's no reason to wait to report the key press, so debouncing should not add latency.

[AlotOfReading]

This technique is highly susceptible to noise. I had implemented this in a prototype game controller years back to get latency down and it was plagued by phantom keys when people physically bent the PCB.

[dogma1138]

There is a reason because many mechanical switches can be partially actuated, spark and depending on the matrix you can also have cross talk which why you need to wait to make sure it’s an actual key press not the switch just ratteling or some noise on the same line.