All of the Elaeagnus species (Autumn Olive, Goumi, Silverberry) are nitrogen fixers. They take nitrogen out of the air and put it into the ground through a symbiotic relationship with a bacteria that lives in their roots, thereby improving the fertility of the surrounding soils. The shrub species of Elaeagnus are sun or shade tolerant and can be interplanted with larger nut trees to their benefit. Autumn Olive was so widely planted on mine reclamation sites in the mid-20th century that it has extensively naturalized in some regions.
In some Eastern and Midwestern states Autumn Olive has acquired a reputation of being a potentially invasive plant. We've grown Autumn Olive for 30 years and in all that time have observed two volunteer plants. In the mid-20th century millions were planted on mine reclamation sites since it is able to "fix" nitrogen out of the air and put in the soil, improving the quality of the soils much like clover does. Since the plant produces masses of fruit that birds love to eat it doesn't surprise me that it's spread out beyond where it was planted. Birds do tend to fly around about and the seed then gets widely dispersed. Autumn Olive is very widely adapted and will grow in the sun or shade. We planted it as an understory in out walnut orchard as walnuts are heavy nitrogen users so they grow faster with an understory of Autumn Olive. It is a shrub so its spread could be controlled by netting it with bird netting just before the fruit ripens in September, since birds are the primary agent of seed dispersal. That way you can enjoy all the fruit and not have to worry about it spreading.
Young seedlings of Elaeagnus can be fairly thorny, very useful for a hedgerow. Older, mature plants and named varieties grown from cuttings have few if any thorns.