In an aquihire, they typically ARE buying the product to get the talent capable of building the product in question.

Let's say you've built some product capable of receiving millions of http connections a minute from thousands of servers and then distributing those to thousands of servers as they request a new batch. But you can't find a market. However this is (was of course) a real-world problem for Twitter.

Suddenly you are a really attractive aquihire. Maybe they'll use your tech, but more likely they value your problem solving experience in their specific problem domain.