The main advantage of self-aligning car-mounted tow bars is the ease of use. When towing a vehicle, you have to line up the RV and the vehicle being towed perfectly. Being off by a matter of inches can make it impossible to hook the two vehicles together. With self-aligning car-mounted tow bars, however, you need only get close to the correct alignment. The tow bars will adjust to keep the vehicles properly aligned. Because of that, car-mounted self-aligning tow bars are pieces of towing equipment that really make the job easier.
Car-mounted self-aligning tow bars are different from other self-aligning tow bars because they're mounted on the car, not the tow vehicle. Because they're mounted on the car, they tend to be lighter weight than other tow bars, which makes them easy for individuals to use. However, they can't just be slapped on any car. The car-mounted tow bars need to be compatible with the car being towed. The car may also need some accessories, like skid plates, to avoid being damaged by the tow bars.
Mounting the self-aligning tow bars on the car means that the bars can stay on the car. This makes them very convenient, but the extra weight of the tow bars can negatively impact the car's fuel economy. The extra weight also causes extra wear on the car's suspension, and if the car is involved in an accident, the tow bars can cause more damage.