Enslavement.

Everything else, resources, energy and other things, can be found in space. This is why most of the SF that has aliens coming after our water and stuff is ridiculous.

Absorbing our culture and the things we can do that are uniquely human would be attractive to an invader. Assuming they're advanced enough not to need our raw labor.

Of course, with luck, our civilization would be even more attractive to a trader. It's harder to be a trader than an invader because you have to have created value to trade. A conqueror just needs raw power.

Here's hoping the Outsiders find us before the Kzinti do.