Yeah, it seems like there are similarities between dealing coke and fraud, but also distinct differences. A coke dealer would be more like a general salesman, whereas many people who commit fraud would be in a position more like a lawyer. As a lawyer, you would have a fiduciary relationship with your client, and those committing fraud are often able to commit the act by taking advantage of the relationship they have with the "mark". The coke dealer by contrast often doesn't even know the person he/she is selling to (or at least not very well), and there is less trust and connection needed for the transaction. So, theoretically, the coke dealer and the person that commits fraud are quite different.
(Note: Yes, Theo, I know you will likely say that one can commit fraud without knowing the person, such as credit card fraud, but it is still taking advantage of a person at a very different level from dealing coke because it is still an intrusion into another person's confidential matters.)