It seems like a helpful technology, but with just about any other "safety" technology in a vehicle, it leads to lazier driving habits.
Backup camera, lane keep assist, emergency braking (can't remember the name off the top of my head), blind spot monitoring, etc. all these are great technology that should help aid a driver, but instead the driver becomes reliant on them and therefore becomes a lazier driver. Not looking over your shoulder when backing up, not adjusting mirrors properly, checking over your shoulder when changing lanes, and so on, all become dying habits thanks to technology.
I think this is one of the better ideas out of there, but again, it all comes back to the driver being less aware of other scenarios other than what's in front of them. The driver behind the truck could be paying too close attention to that giant distracting screen. I mean how many times have you had a car behind you while you were behind a truck? What if that car behind you decides to try to pass before you do and you're too distracted by that giant monitor on the back of the truck? BAM! You've been rear ended OR you've hit the side of someone else because you were more concerned of the traffic on the opposite ahead of you and not the driver that was behind you.
My daily driver has one technology I know I can't live without though (and it's the only safety technology in it), and that's the backup camera (doesn't even have trajectory guidelines). However, I do not rely on my backup camera to show me whether traffic from either side is coming or not, I still turn my head and look behind like you're supposed to. The camera is used for one thing, it's true purpose, parking. Parallel parking has become so much easier with it and so does backing into spaces if there are objects behind me such as a bush or lamp post.
People are careless enough drivers as is. Let's not add high speed mobile monitors to the mix, even if the intention is to save lives. Great idea, but I think Samsung underestimates the quality of drivers out there.
Just my .02