I think people choose DDG for its emotional appeal (they like that it's a small company, privacy benefits, all kind of reasons besides search quality). Later they rationalize about it being better.

Frankly, I think this is morally wrong. When they use an inferior search engine, or inferior maps app for that matter, people are dumber than they might otherwise be. They miss a boost of intelligence, perhaps not IQ, but they are less effective operating in the real world. The world as a whole is worse because of it.