Enclosed Carrier Auto Transport
It is deemed to be the safer method of car transporting but just like gold is more valuable than bronze, we cannot all have gold. This is the car transporting method where a car is ferried in a closed truck to its destination. Sometimes the vehicle being transported is so valuable that exposing it even to site may expose it to some unusual dangers like being stolen on the way or tiny scratches that may devalue the car in a big way.
When a car is transported this way, it is protected from the natural elements like bad weather, dust, and grime. Loose stones and falling rocks also are not a danger to a car being transported in an enclosed truck. So why doesn't everyone transport their cars this way? Main reason is obviously the highly prohibitive cost. The cost of enclosed transportation is very high compared to an open carrier that most simply cannot afford it. The transporters are also not that many so one has to book way in advance and because they are so few, getting one when you want it is never a guarantee. 90% of carriers plying most roads are open carriers.

So then, when is it appropriate to use enclosed carriers? For those transporting rare custom made sports or private car, a rare vintage car, or an antique, this may be the more advisable way of doing it. These cars are so priceless that a minor scratch and a tiny dent on the body can greatly reduce the value of the car so to ensure their safety and prime condition; one is well advised to transport them this way. After all those who own such cars are not hard up financially so it's never a big deal. It is also very appropriate for cars that have a very low ground clearance and cannot be practically driven on conventional roads; here we are talking about a racecar for example (an F1 racecar) which are so expensive.
So much as this system is costly, it has its place and time, for a few dollars more, and your car is assured of safety and good condition maintained.

Special cars, such as one with specialty accessories, wide rims, enormous tires and ornaments going this way and that, should be getting covered transport in order to ensure that like the first example they don't get damaged along the way. EnClosed-transport services, unlike open-transport ones, are not fussy about car specifications. Cars with unusual dimensions could be damaged while loading on or off the transport truck. It could also be knocked loose in transit. If your car has irregular or unusual specifications, you are better off considering closed transport. Closed transport does cater to a limited scope of clientele because it fulfills certain specific needs. However, if you are one of the people with such needs, then you really should get some cover for your beloved automobile.
So the most obvious benefit of getting closed transport is that your car won't get as much damage or wear and tear in transit. Sure, cars that are transported using those open vehicles you see on the highways are not really damaged, but they get some wear and tear because of the debris and whatever elements they encounter while on the open road. By getting covered transport, you protect your car from such damaging factors. You have to get covered transport if your car is the type that simply cannot get damaged or cannot age. Collectors item cars and vintage models all fall under this category. If you have one of those, then your obvious choice is the enclosed auto carrier method of transport despite the extra cost.