Well you would sort off get a 360 view.
The problem is the side cameras, not least where to install them, the issue is curtain airbags deploying.
My last side system was the K2S system, it have super small remote cameras, and wedge shaped too, so putting them on the fixed glass part on my rear doors i was pretty sure the airbag would not rip them off at least.
But the lenses on these cameras are geared for front / rear use and so with a front / rear camera of anothe system, you have to be some ways away from the car before you have a actual overlap of the cameras.
But i was still pretty happy with the setup, even if using 2 different systems the recordings was not in sync, so to get that you can use a auto sync feature you will find in most video editor tools.
I whipped up this video back in the day to demo my setup. ( not synchronized )
The kit you are looking at, well the cameras are pretty big and so would be tough to install in a car.
you also have to be careful with these kind of systems, you can risk that it record in pretty low resolutions and / or FPS, and also the bitrate can be pretty low too.
Really they are not so much dashcams but more surveillance cameras for vehicles like taxis and bus
10 or so years i ran such a 4 channel system, but back then with low resolution cameras like we saw on TV as kids in the 70ties.
The coolest part was my front camera was a box camera with 27 X optical zoom, so i could get really close to a plate way out ahead by using the zoom function. but that box camera it was lik 3 X 3 X 6 inches or something like that.
In consumer dashcams not many make the remote main unit kind of systems, and the ones that have made them, well they say that the kind of system do not sell well compared to traditional systems.
I really prefer the remote main body as IMO if you do it right, it would give a range of performance upgrades.
Like:
You can make a actual cooling solution, maybe even have active cooling, this will be good for running really high bitrate or many channels, and also as you can put the main box somewhere where it do not get direct sun while parked, well for parking guard duty, it should last longer before it have to tap out due to too high temperatures.
Ordinary dashcams have a measly little ALU heat sink inside a little box and no active cooling, and you dont really get convection in a little box.
With a remote box you can make it " large " so it could house a actual heat pipe or vapor chamber cooler, maybe even a fan.
You could also instead of a stupid little memory card have say a 2 Tb solid stade M2 drive or even just a SSD
