It was a bit simplistic of me to summarize it as a payment gateway, it was actually 50-60% of their backend systems that was enhanced, it was called their "Big Data Project"

They do do fraud detection on the deposits, because of anti-money-laundering. The DL models also monitor various other types of abuse (bonus abuse and in-game abusers). They also are experimenting with Deep Reenforcement Learning to actually play some of the games

An online betting system has to do fraud detection on a higher level than random merchants, since they can expect to be a target for large scale non-amateur fraudsters, and just as in any other business, if your incoming payments are fraudulent, you lose that money.

Perhaps for anti-money laundering compliance.

Well, I think random forests on a feature set probably plays a big role and is probably easier. But to use a deep neural network maybe, you might be able to get away with a convolutional network to extract higher order associations among some input set.