Generating data is good, as long as it's limited to metrics about the vehicle and its use. It can help diagnose issues. It doesn't have to leave the vehicle though. Garages can simply read it locally when required.
No, generating data is NOT good. Garages would read metrics and upload them. How is that any better?
Error codes for faults and nothing else are enough.
What caused the fault? In the case that the error code encodes everything you actually need to solve the problem, sure, but having used OBDii readers I doubt that's universally the case. If you'd like to pay the mechanic more to diagnose the problem, sure. It seems it would be better to make it illegal for the mechanics to upload your data without your consent though.
Yes cause laws have been so successful at preventing unlawful upload of data.
Guess everyone should define what they mean by data. An error code is data. Pretty much any kind of information is data.
Not in the EU, an "Event data recorder" which records speed and inputs (pedals) around the time of a crash is required by law.
Every car generates data. Just look at the odometer. Which is also often required. Or at the very least, would otherwise require you to be keeping track of mileage. So it wouldn’t be the car generating data, it would be you generating it.