This response, though frequently used, is wrong. If my data is useless they wouldn’t collect it. They use this data to target ads specifically for me, increasing those ads value. So yes, individuals data is worth something.
That's not how ad targeting works. Your data is used in aggregate to target ads to your purported demographic, and that designation is usually obtained on-the-fly via your recent page visits. Storing your individual interests isn't worth the money it costs.
That said, this has nothing to do with ads. It's a matter of foreign intelligence.