Yes, this happens because sweepstakes are regulated differently. For example, the platform https://www.jumbo88.com/ clearly states that it operates in almost all US states, but there are exceptions where participation is not allowed. There are also age restrictions (most often 18+, but in some places it is 19 or 21). When I registered, I was asked to provide documents (KYC) to confirm my age and region. At first, I was annoyed, but then I realized that this was actually a plus, because it means that everything is official and honest. So, it’s better to check the list of available states/regions once than to be surprised later.