10,000 tons is equal to four hundred Space Shuttle cargoes. Further, getting asteroidal materials is not risky business, like launching materials up from Earth or the Moon. The gravity of the asteroids is negligible. A person can jump off any but the largest asteroids with leg power alone. With asteroids, all we have to do is nudge them a bit so that they pass close to Earth's moon, and the Moon's gravity will divert them into Earth orbit.
Asteroidal resources are unique and diverse.
In general, they are different from the dirt beneath our feet and the ores that we mine from our planet's crust. Likewise, they are much different than the Moon, Mars, etc. Asteroids are much more metal-rich, like the core of the Earth, Moon, Mars and any other planet. The asteroids are normally not as enriched in oxides, silicates, and the other lighterweight elements that floated up to dominate a planetary crust. Asteroids are more like a mixture of a planetary metal core plus a mantle and a crust.