Yes.. Bitcoin offers 100% anonymity, as long as you are storing your coins in a wallet which doesn't have any transactions made to KYC-enabled exchanges. Since it is a digital asset, you don't face any checks at the airport as well. It can't get any better than this. You can first convert fiat to BTC in Thailand and then travel to a country such as Cambodia, where gambling is legal. And there you can convert your BTC to fiat and visit the casinos. If you win big amounts, then once again you can convert it back to BTC and travel back to Thailand.
If these countries you've mentioned support crypto then it's easy to travel with huge money in your bitcoin wallet, but if not, it's still useless. Exchanging your bitcoin in countries where p2p is the most popular is not easy, especially if you are a tourist, correct me if I'm wrong.
Or he can use the third service to help them convert their bitcoin easily, so they can use that money for whatever they want. Maybe that will not be easy for them, but I think they will search for the right answer by getting information from the internet. With the internet's help, I am sure before they travel to the other country, they will make sure that they have enough information about the destination country so they will not get into trouble while they stay.