This could be used to direct policing resources sensibly ("lots of incidents recorded at such-and-such a place, maybe we should patrol there a bit more") or to build a dystopian database, or to waste police time. There's certainly a push by some of the media to stop the police spending time on this and focus on solving crimes instead.
Similarly, this regulation could be used to prosecute child abusers, or it could be used to suppress free speech, or it could mean that people start using properly secure messaging apps.