I just don't see the few cases where it's enjoyable to be worth the other costs. I'd consider it similar to smoking in that regard.

Smoking is a much greater nuisance than driving, because a nearby smoker will foul the air for a fairly large radius through no choice of the people around them. Driving only affects other people who choose to be on the road.

That's not true at all, the incidence rate of lung cancer in smokers is less than 20%. That's still much higher than for non-smokers (0.4% - 2%), but hardly a "virtual guarantee".

With a Google car, I'd a) be able to send her by herself and b) even if I had to come, I could work on the way, meaning I'd have more than a week's worth of vacation/sick time restored.

Yes, I'd happily accept ads.

True privacy is very hard. You could set up a camera to read plates at some choice points and know the whereabouts of most of the people in your city. If you want to do something privately you have to act deliberately in this day and age.

To set up such cameras, you'd need permission from our National Data Protection Commission and if you were to store footage with car plates you'd fall under the Personal Data Protection Law which requires you to either get explicit consent or fall under one of the few exceptions in the law (and no, tracking random people isn't one of them).

And even if you qualify, you can only use that data for the specific purpose you said you needed it for and it needs to be well protected (for example, a governmental CCTV installation was suspended because the recording weren't being well encrypted).