I think one of the unique things about the eruption, often overlooked, was how accessible it was for the USGS as well as television media, and that its the only volcanic eruption in the 48 contiguous states in modern history.  Much larger eruptions on far-off Pacific Islands didn't hold as much interest in the U.S. as one in our own backyard, and I think because of that, and how much more readily the USGS could get personnel and equipment in to study the 1980 eruption of St. Helens brought a lot of breakthroughs to make it easier for scientists to recognize the warning signs about an imminent eruption in a volcano.