In the old days bankers drafts were as good as cash, however these days there is a lot of fraud associated with bankers drafts. I would treat it cautiously and treat it as a cheque, especially if someone is buying a car off you. If they were really desperate to get the car they could pay cash (like I had to when I bought a car in January this year).
Be careful! I've read that banker's drafts are now amongst the easiest ways to carry out a fraud. Don't part with anything until you have the money in your account and the issuing bank has had time to flag up any problem EG 6 working days as a minimum.
Don't part with the goods until the draft has ben converted into cash. They are simple to produce fraudulently and many dud ones have been used to buy cars.