So your iPhone—and probably your computer—now both have a file that mirrors data that was previously limited to law enforcement, which itself was only able to obtain it from a court order. Without encrypted backups, someone who has access to your computer can see your whereabouts. "By passively logging your location without your permission, Apple have made it possible for anyone from a jealous spouse to a private investigator to get a detailed picture of your movements".
This is scary. We still don’t know why that file even exists, but it must surely have a purpose that Apple so far hasn’t disclosed. Whatever it is though, there is no excuse for just leaving the file there unprotected. The bare minimum precaution that they should have taken is encrypting the file. There are many disturbed people out there.