Is it necessary to make the loud sound of the feet when we lift? No, it is not necessary. Many athletes don't move their feet at all, and they do quite well. However, I do believe in shifting the feet; I teach a relatively narrow start (jumping stance) into a wider catch (squat stance). I encourage athletes to make the loud crack of the feet to promote foot balance and stability, but NOT because it sounds cool.
In my opinion, the athletes must land flat-footed to avoid a wobbly catch. I realize that a beginner trying to make the loud sound puts the them at a risk of a large hop, instead of a low shift. An athlete jumping too high is unfavorable and there is a way to make the sound without the unecessary airtime. I have my athletes SHIFT their feet, not JUMP their feet. To correct this error, cue athletes to shift their feet as they pull themselves under, rather than shifting their feet as they extend.