The QAZ keys on the right is a joke. This keyboard layout is called a QAZ/35% layout, where the Q, A, and Z keys are gone. The Esc, Tab, and Shift keys on the left side default to typing Q, A, and Z respectively, with further keys hidden behind chords and layers.

I believe OP is making this keyboard as a response to someone's reaction to the QAZ board, right here on Lemmy.

To answer your question, many people prefer smaller keyboards mainly because 1. they're gamers and want more space for their mouse, and 2. smaller keyboards minimize hand movements and therefore are more ergonomic.