I think you may have causality reversed. Without Palantir, law enforcement would not only have no use for the data, it probably wouldn't be able to even collect it in a meaningful sense, in terms of technical and financial resources.

Palantir goes to the agency and says, "Give us data and we'll give you "actionable intelligence".

You know, back in the 90s and early 2000s, the term "data mining" was perjorative. Financial operators would look through their mass of data for correlations and sell them to people who would discover that they didn't actually work.