Maybe they could grow space dope there.
That's how European colonialism financed mercantilism in the 17th, 18th and 19th centuries.
Tobacco, spices, tea, chocolate, coffee, sugar. And then there were luxury goods of little intrinsic value, but which rich Europeans could now afford with all the money they made from the slaves they needed to work the land they stole: Inca gold, Aztec silver, furs, indigo.... And of course there were naval stores (wood, hemp, pine tar, and cotton) they needed to maintain the fleets they needed to secure their sources and markets.