Divine Finger Snap became part of wuxia lore because it was used by East Heretic Wong Yerk See and his followers in LEGEND/RETURN OF THE CONDOR HEROES, but when TVB adapted Gu Long's CHOR LAU HEUNG in the 1970s, this martial art became Chor Lau Heung's signature martial art as well.
Did Chor Lau Heung actually use this martial art in the novel? I've heard various things. Some have told me that he didn't use it at all; others said that he did use it, but it wasn't his signature skill and he rarely exhibited it.