I am not sure which ones are allowed but I know that USA is not allowed for online gambling and I do not really know why because they are the biggest gambling country in the world money wise with Las Vegas making the most out of any casino in the world. 
the government protect his business.
Online is V.S. Offline.
if you can easily bet online with fairness, you will not got to Las Vegas for small bets.
just bet in your bedroom . or in bed