Depends on how the hiring critera for the next stage go. If HR filters out everybody with less than a 3.5GPA right from the start then the C student who knows the stuff will never even get a chance, while the cheater will have the opportunity to bluff their way through the interview.

Depends on your goal. If you can get a higher GPA by cheating and don’t plan on using the actual knowledge…

Better by what measure? Not by "get the best job after college" certainly.