There are currently no laws in any country that prohibit people from betting cryptocurrencies in online lotteries and casinos.
At the same time, in some countries the use of cryptocurrencies is generally prohibited, and this list includes Algeria, Bangladesh, China, Egypt, Iraq, Morocco, Nepal, Qatar and Tunisia. Another 42 countries restrict the circulation of cryptocurrencies, warning financial institutions against accepting payments in cryptocurrencies.
You may also find that some gambling websites in your country are blocked by Internet providers. The reason for this, most likely, may not be a direct ban on cryptocurrencies, but the absence of a gambling license in your country for these specific websites.
In the EU countries, there are no laws that would regulate the scope of cryptocurrency gambling. In the UK, online lotteries and casinos can operate under strict AML (Anti-Money Laundering) requirements. Cryptocurrency exchanges operate legally in South Korea, but all cryptocurrency payments in this country are under strict state control. In 2021, El Salvador passed a law recognizing bitcoin as legal tender, but no other government in the world has dared to follow suit.
A significant advantage of cryptocurrency lotteries and casinos is the absence of intermediaries in the form of banks and payment services. Cryptocurrencies are transferred instantly, securely and anonymously between your cryptocurrency wallet and lottery wallet. Therefore, even if your country of residence prohibits (or does not allow) using cryptocurrency payment, you can still try your luck.