Is the cyber-war a "quieter risk?"

The New York Times carried an article by Choe Sang-Hun and David Sanger titled "As North Korea Blusters, U.S. Worries about Quieter Risks."  It reinforces some of the points made in my last post.   I only have one question.   In what sense are the cyber war attacks and propaganda a "quieter" risk?  It seems to me that their effects are noisy and very real.