First, LE costs less than 35, not 40. Second, D4 has RMT and it’s 70. So that doesn’t really have anything to do with it. As long as you make more than the game cost before getting banned, it’s still worth it.
That’s how RMT operates and when the devs detect such an operation, you do get banned.
There are lots of scams where people get credit card information. Those are usually used for more illicit stuff like other scams or RMT trading.