Simple, They just want to get an easy way of earning money. Cheating and stealing are part of our human nature. We do have a devil inside of us and we are fond of taking advantage to those people who we know are vulnerable. Scamming has been around in any type of industry, and we can't contaminate those people as they can easily jump from industry to another. Some people tend to scam due to influence of other people, urgency and etc.
I very much agree with this reply; it's a way for people to have it easy in earning money as supposed to working hard and earning it rightfully. Unfortunately, many people are more into that kind of earning, especially when the means to earn is new and they know that they can exploit their chance at another's expense.