I think it best to think about the ads in the same way you would in any other medium. Unless you have a special offer or something, it's just branding. The original hypothesis upon which Google was founded, that people would be interested in buying things if they were searching the internet for something relatable, seems to have failed- at least in the near-term sense. Just because I am looking for campsites in the Rockies doesn't mean I am in the market for a sleeping bag. But to put the ad in front of me then to make me aware of your brand might be useful. That's the game played by advertisers since they began with media advertising.

Given this, all of the data collection/tracking/etc. seems like a round-off error in effectiveness, and doesn't seem to be worth the loss of individual privacy.