I hope you're seeing how this isn't very relevant however to the question whether we want this kind of monitoring.
I also don't see how your anecdote in any way is a long story for 'it doesn't hurt to keep that kind of data'. It's a story for how 'it can be helpful to keep that data as shown by one particular anecdote'. That's not really the point, I think we all agree we could find a useful application with data, the point is that we may not want these things to be monitored for opposite reasons.
Yes, they have this potential benefit, but no, they should not be reviewed solely in that context.
As for Shipman, wasn't it precisely because of anomalies in data collected about him that he was caught? And do you agree that collecting clinical data about doctor's use of drugs, and their outcomes vs. statistical norms might be reasonably exempted from the kind of personal data logging that many people find objectionable [me!]