The problem is that platforms are using that data in ways consumers do not understand, and might not accept if they did. For example, Google bought a huge trove of credit card data earlier this year. Facebook uses image-recognition software and third-party tags to identify users in contexts without their involvement and where they might prefer to be anonymous. Not only do the platforms use your data on their own sites, but they also lease it to third parties to use all over the internet. And they will use that data forever, unless someone tells them to stop.

Especially when it comes to making a decision that will distinguish you from the pack, inherently, the obvious data is not there to back that decision up, or else everyone would have already made it.