US dragnet snooping has nothing particular to do with law enforcement. Nobody is allowed to know what is done with the stolen information. When we find out one use, that doesn't preclude any other use.

The use that nets the greatest return for any snooped information is extortion. Spooks are very familiar with this use, as it is their go-to method to "turn" people to recruit informants. Of course turning is only one of many uses for the same information. Coercion applied to public officials creates corruption, to judges miscarriages of justice, to police persucution of private enemies. It poisons the public well everywhere it touches.

Prosecutors are also very familiar with extortionate use of secrets. We see it in "plea bargains", where people are made to plead guilty to charges prosecutors could not prove in court, but that only scratches the surface. "Constitutional protection" is no shield against any use that doesn't introduce the facts in testimony.

Note that having "nothing to hide" doesn't help you if the secret is about somebody else, and used to coerce their actions against you.