Why do all the hot new slots like Dark Knight and The Mummy come out on systems not available to US players. It is because those USA based games are not really legal and you cannot invest in products with an uncertain future?
Because they are owned by publicly traded companies that cannot be associated with companies that may be doing something that may not be 100% legal.
My question to you is why you’re only targeting US players. There’s a whole world out there looking for no deposit casino bonuses.