This is just like a ponzi scheme, but in the case of this scam, they are trying to convince us that they are getting the profits through doing arbitrage between cryptocurrencies. I don't get how people still fall for these kind of scams.

Just like a ponzi scheme, if you are able to withdraw your money, it doesn't change the fact that after a while the site will close and you'll be holding the bag (not even the bag in this case).