Yeah, the simple answer is: to save on taxation.
This used to be a very common thing to do back in the 90s and early 2000s. You buy an expensive car (often american) remove the back seat, mount an iron grid behind the front seats, thereby creating a separate goods compartment.
If you have a company, the car could then be registered as a commercial vehicle - either fully commercial or semi-commercial.
A fully commercial vehicle would only be allowed for use directly related to the company.
A semi-commercial vehicle would still be associated with the company, but could also be used privately. Between 1969 and 2009 the plates would be the same as for fully commercial vehicles, so in order for police to quickly determine what was what, owners of semi-commercial would get a sticker to place on the windscreen.
In 2009, the reduced-tax commercial plates were reintroduced after a 40 year hiatus. Often called parrot-plates because they are multi-colour (the prefix-section has yellow background, while the numbers are on a white background) - these plates are now used for the semi-commercial vehicles, but owners were not required to change existing plates.
This Camaro, however, is not a semi commercial, it's fully commercial, so only allowed for use in direct relation to a company. The way you can see this in the vehicle registry is to look at the field called "Anvendelse" (use), if it says "personbil" it means standard passenger car, "Godstransport (privat/erhverv)" (Goods transport (private/commercial) means it's a semi commercial aka "lower tax", but if it simply says "Godstransport" (goods transport) it means the car is for commercial use only
In addition to the removed rear seats and the iron grid, you'd also need a couple of other details. 1. there should be a visible weight table on the car, showing the max allowed capacity and 2. the name of the company should be written on the side, clearly visible. This Camaro doesn't seem to live up to any of these conditions, but although not strictly legal, this is not unusual. I think this is due to the fact that you could apply for an exception to the rules "under certain circumstances" - this could include hearses, transports of exceptionally valuable goods (for security reasons), various state agencies, bailiffs (and other similiar "sensitive" fields of work)
Because of these many exceptions, the rules tend to not be taken too seriously and many small companies tend to often "forget" about them. A few bigger transport companies also suffer from this forgetfulness... especially if they have a dubious reputation and have often been caught using illegal workforces. In such cases, they don't want to be recognized by the public, or - more importantly - law enforcement.