I'd rather 100 people know 1% about me than 1 person know 100% about me. Even if the only thing duckduckgo did was spread knowledge about me thinner, it would have value. Google already has most of my email (because most people I send emails to use gmail) and my youtube viewing history. Giving them my general search history as well isn't something I'm keen on.

Duckduckgo isn't perfect but they're better than google. If I knew of something better than duckduckgo, I'd use that instead. But I'm not going to let perfect be the enemy of good.