I suppose another benefit might be the fact that volcanic slopes are often rather inaccessible, especially if they are steep. Thus they can provide refuges for rare plants and animals from the ravages of humans and livestock. Scott Rowland Volcanoes have done wonderful things for the Earth. They helped cool off the earth removing heat from its interior. Volcanic emissions have produced the atmosphere and the water of the oceans.
Volcanoes make islands and add to the continents.
Volcanic deposits are also used as building materials. In the 1960's Robert Bates published Geology of the Industrial Rocks and Minerals. He noted that basalt and diabase are quarried in the northeastern and northwest states. High-denisity basalt and diabase aggregate is used in the concrete shields of nuclear reactors. Pumice, volcanic ash, and perlite are mined in the west.