I suspect a lot of the fascination is because the information can be used to improve our quality of life. I suspect the cynicism comes from those who have the most access to this information using it to improve their quality of life at our expense. (That, and actually making use of the information takes more effort than most people are willing to expend.)

I have always been leery of data collection, but I have my own parallel: there was a lot of optimism about the benefits of personal computers in the 1980's and 1990's. Of course, that was pushed by the industry itself. I have since realized that what was happening then was not all that different from what is happening today. The outcomes were different because the tools were different, but it basically reduced/reduces to a bunch of people trying to enrich themselves by promising one thing and delivering another.