Absolutely, conceptually its strengths lie beyond simply covering up. Though, its as natural a reaction as any, to lift your arms up to protect yourself. Its as natural as any to grab(lop), but the concepts behind grabbing are what empower it…
The bong, like every technique, is variable. The elbow being down is similar in structure as the elbow being up, its just a variation. Still bong sao conceptually. Thats where we all get confused is that the rehearsed motion is static. Its not, its an idea which is infinitely variable. Thats where expression comes in, how you choose to utilize that variable idea at any given moment.