That's a really good point that I hadn't considered before: sometimes the ad that maximizes the expected return won't be the ad that is most accurately targeted

That's a really good point that I hadn't considered before: sometimes the ad that maximizes the expected return won't be the ad that is most accurately targeted. If an ad for a $10 HDMI cable for your new TV snags 10% of consumers, that's a well-targeted ad, but if 1/200 consumers will purchase another $500 TV if you remind them about it occasionally for the next six months, that's the ad it makes sense to run.