I don't see what's bad about it though. I'm sure it can assist with intelligence analysis in a number of ways, patterns of crime and reporting which can be useful for helping to spot, for example, trends in fraud such as fake insurance claims and, subsequently serve as useful evidence.
I'm sure if comes into play with other useful evidence as well, like recording 999 calls and similar. Similarly tracing witnesses and people with useful information, I'd say the person calling something in could be vitally important, even years down the line in some cases.
I have no problem with the police having my details. If something happened and they needed to get hold of me urgently for some reason, I'd rather they have my contact details than not.