Each layer of difficulty reduces the number of adversaries you have to deal with. Check your spam folders to see how many are incredibly basic and easily caught with the simplest tools.
Moreover, fraudsters are generally lazy. If fraud that works against somebody else doesn't work for you, the fraudster won't go after you until they've saturated all the “somebody elses”, which may be a long time. I used to work in fraud detection in adtech, there was a lot of low-hanging fruit.
