And beyond that, of course there is potential for harm if data is collected for targeted ads. It might be increasing the price of your flight because you've been looking at the target country several times in the past weeks. It might be canceling your insurance because you googled for headache medicine. Or it might be marking you as a person to be deported into a "reeducation camp" because of your heritage or religion thanks to data that was involuntarily collection about you (originally without evil intent, even). Most of these already happened in reality.