The first valuable thing on Earth is life. Life may be rare enough, or diverse enough, that worth sampling the unique life on Earth. The intelligent monkeys can

The first valuable thing on Earth is life. Life may be rare enough, or diverse enough, that worth sampling the unique life on Earth. The intelligent monkeys can be useful, but can be knocked down is cause problems. The second valuable thing is intelligent life. The intelligent monkeys are worth preserving and talking to. But their advanced civilization has lots of potential dangers so need controlling protectorate. The third valuable thing is better minerals. The active processes of the Earth concentrates minerals. They could grind up a whole asteroid, but cheaper to take from Earth. Also, biologic processes make minerals; vacuuming up coal is cheaper than making it. These wouldn't be whole civilization but pirates grabbing some cheap loot before the authorities and natives notice. The fourth valuable thing is Earth itself. Inhabitable planets are rare. The expected way would be apocalypse or annihilation. But I think it would be more interesting to have alien invasion where they ignore us. They settle the arctic, and don't do anything until attacked. Then they start removing CO2 until the temperatures drop and ice age returns.