Yes that is true, but I still think it was a good trade (I firmly believe that the car he sold for 800 steem (600usd) will defintly be worth 3k+ in a few months.
Apart from that, if he wanted to get rid of his car and gain steem, If he traveled the most used road (changing usd for w/e coin and later trade those for steem) he would have had to pay a lot of fees.
In his trade now he paid 0 fees, so it still is a gain. (in my opinion).
He could only make this trade because he knew someone who wanted to buy a car with steem (i can tell you those peopel are hard to find.