Not sure what the T&Cs are there, but usually there is a rule about minimum value of deposits when you do CPA.
On
CAP you will see dozens of complaint posts because the casino closing the CPA affiliate account - usually it turns out there is a clause in the T&C about it.
There used to be a lot of stuff going on years back, where players would sign up as affiliates and get a CPA deal, and then send all their friends to make minimum deposits and the casinos would pay out 3x the amount they took in.
Obviously no business can exist like that, so they created the minimum value T&Cs.