Yes, aggressive driving is a bad thing--but it's not something easily detected by a sensor.
I could easily fly up the shoulder at 40mph in a 60 zone bypassing all the stopped traffic.
Could drive down the sidewalk at a 20mph pace.
I can still weave though traffic as long as I don't go too far over the speed limit (assuming this device tracks location and speed).
I can still tailgate the fuck out of anybody.
I can still use my phone while driving.
I can be completely wasted and probably not set the thing off.
But don't you dare hit your brakes too hard!!!
It's a failure of the industry that they tend to market this monitoring as all about the driver. It's really not, it's just conditional probability.
To underline this, I had an enlightening moment with my auto insurance company years ago. I worked a handful of miles from where I lived, but the only way to get between the two was a freeway that is infamous for not only being highly congested (my average commute was a 45 minute drive each way), but for the numerous accidents that happened on it.
I moved much closer to my work, and when I updated my insurance policy with my new address, my premium was cut to nearly 1/3rd what it was before.
The final straw for me after a few months was another driver running a stop sign and feeling my brain waste milliseconds deciding if I should hit the brakes as hard as I should or juuuust hard enough to avoid hitting them in hopes I don't get a beep. I did the latter and it beeped anyway so I ripped it off the ODBII port and threw it on the floor. I changed insurance companies the moment I got home from work.
My final score was really poor and I was pissed since I'm the slowest and safest driver I know.