The biggest gripe I've got with any sort of telematics which sends driving-related data to anyone, including insurance companies, is not the data itself but the poor interpretation.
Anyone who's done some sort of advanced driver training ( most likely in the UK, I've not seen it very prevalent else where) of the likes of IAM or RoSPA's ROADAR scheme ( https://www.iamroadsmart.com/ or https://www.roadar.org.uk/ ) will drive considerably differently than anyone else, and safer. That doesn't preclude firmer braking or harder acceleration, but both those activities would be pinged by
And a friend was hit by a young driver with telematics - he was too fast round a bend on a country round and while she stopped in a few feet, his marks were measured at about 45 yards. Telematics don't make things safer at the time, they tell you after the fact (or possibly not - what's too fast on a 60 mph piece of road where in reality 25-30mph is the top safe speed in the case above).
The way to better safer driving is to give the human the skills and the attitudes to deal adequately with anything the road might throw at them, and the only way to do that is to offer good insurance discounts for people with a demonstrated desire to improve their driving. But that's not going to happen unless it's mandated, so I'll keep my as-little-computerised-as-possible car off the Internet and drive it in the way I've been trained, and out of the way of everyone else out there who's not.