The BRS still has you decending at a quick-ish rate - the undercarriage then cushions the landing some more. This should mean that you land without injury.
Doesn't work too well over water though - I believe someone landed one in the Hudson, and because the undercarriage didn't aid in the deceleration upon impact, the body of the aircraft impacted on the water at it's full speed of decent, leading to a very sudden and rapid deceleration, much higher G-forces were then experienced, and it led to a broken back for the pilot.
We dont know if it would be relevent in the NY incident either. I believe the BRS is not supposed to be deployed at cruise speed.
There is no technology or gadget that will make all air travel safe - everything has it's limits.
The BRS is, however, a great idea. If you are in a situation where you cannot glide to a safe location to attempt a emergency landing, and you have no options left, then it does increase surviveability (any chance is better than none). It just seems that people may attempt to utilise the BRS when they haven't exhausted all other options. Lack of education possibly leading to user error?