Offshore betting sites may be acting legally based on the laws in their home countries, but it doesn’t mean they are legal under US law.
The Unlawful Internet Gambling Enforcement Act of 2006 (UIGEA) made it illegal for the US financial system to process transactions to gambling sites that don’t comply with US law. All online gambling sites that are not licensed by a US state will inevitably breach the UIGEA if they serve US customers.
There are good reasons to join the state-regulated market:
Better betting options and software.
Deposits and withdrawals are fast and certain.
You have legal protection for your funds.
Introductory bonuses are generally better at US sites because players’ average spend is higher.
In-game betting is rarely available at offshore sites.
Revenues that flow offshore do nothing for the local economy.
Your money is not safe offshore. Many sites have gone bankrupt leaving no way for customers to get their deposits back.