It gives the insurance company a way to identify a lower risk group of drivers so they can charge that group lower prices.
But it's not hard to see how nearly 100% of people who drive recklessly would avoid such programs, but less than 100% of good drivers would.
The statistical skew makes sense to me. I doubt that insurance companies are assuming that every driver who doesn't take part in such program are bad drivers, but insurance is purely a game of statistics.
Is that true? The handful people I know who have/had these devices are definitely wouldn’t fit that category. And most removed it after a while because their premiums went back up (because of their driving). They just chose it because it offered cheaper rates and they all said the companies promised it would not raise rates above what they were already paying. So it was a “what do I have to lose” decision.
Obviously anecdotes aren’t data. I think it makes sense that the drivers that are egregiously unsafe (and know it) will avoid them. But it would take seeing actual data to make it clear to me that the majority of people who consent are safer drivers.