At the end of the day this is like self canceling turn signals. I prefer to choose when my lights are on, not rely on automation. It's up to me to manage and proactively signal my intentions to others, and be aware if they are responding to them.
Developing the muscle memory of tapping the brake, lever or pedal, when slowing will serve you well. Relying on some automatic feature is fine, until it fails and you are un-aware of it. Never mind the negative aspects.
I see too many negative responses to my wife's factory self canceling turn signals. I've only had a HD that had that feature and it was only useful about half the time, the other half turning off too soon or staying on too long. Which is what I see with the wife's BMW. I've seen her cut off because someone thought she was turning left, so they did too, except they were on-coming. A lot of other things too.
Back to the enhanced brake light with G sensor. You want something to do what you can already do manually. Hoping it will make you safer. It won't. Only you paying attention to what traffic behind you is doing will make you safer. How you choose to respond to that traffic's actions will create a safer scenario for you.
Things like: stopping at an angle, aimed for the gap between cars
Watching the traffic behind you, not just the one car behind you at stops
Looking for traffic behind you when you are slowing for any reason and when they are present, tapping the brakes a few times if they are closer than you like, then checking that they actually respond to your signal
Hand signals to vehicles following too close (not a single finger gesture). An open palm, turned down with a patting motion usually communicates to the driver to slow it down/back off some.
Weave in your lane to ensure others, both behind and on-coming, see you. The human brain notices CHANGE more than anything else. A single point closing in is not CHANGE. This is best suited to coming up on intersections where you might get 'left turned' or fast approaching traffic from the rear.
We always have to be prepared to avoid other drivers. It really doesn't matter who is right or wrong, has right of way or doesn't, we'll still lose the fight if we share the same space with larger vehicles.