What is the point of buying your own trailer in the game?

The obvious reason a player would buy a trailer is the efficiency and the earnings for each ride. Usually if you don't have a trailer and go by the usual "get the job" you get a trailer with cargo while paying you smth like 2-4K in game currency, considering the losses such as damage penalty and time penalty etc, you would get around 1-2K in game currency. However if you bought a own trailer the earnings for each jobs will increase significantly like 10-16K. Hope this helps