I would not say that this part (the fare classes) is fraud - if the rules are stated beforehand and are clear, then it is not fraud. Actually this could turn out to be a pretty good deal.

Not to say that they are not overly-complicating things intentionally to make it more difficult to understand than it seems.

Here is the part that I think may be considered, in a way, fradulent: when you go to use the award ticket, is it subject to the same ridiculous, hidden capacity controls that the mileage standard level awards are subject to? If it is, then it is, to me, fradulent. If they say that you are getting a free flight, then they should give you one if the flight is the seat is EMPTY, not if one is available per their undisclosed capacity controls. The reason is that they are the only ones that can determine if you can have a seat and it is a completely closed system. The whole plane could be empty and they might say that you cannot have a seat because they did not allocate any seats on that flight. Your award could expire because you could not use it because everytime you tried to use it they said that there are no seats available. I have not confirmed that this is how it works, but is says in small print: "All Delta SkyMiles program rules and conditions apply." I would call them and hash out all details before using the program.

Nonetheless, provided the award is reasonably usable and you can go anywhere, this can be a pretty lucrative offer.