Crypto casinos accept deposits and withdrawals in cryptocurrency rather than through a bank. In practice that usually means faster payouts, since a blockchain transfer does not wait on banking hours — but it also means the licence and the bonus terms deserve the same scrutiny as anywhere else.
Usually, because a crypto transfer does not wait on banking hours or card processors. The casino still has to approve the withdrawal first, so the operator matters more than the currency.
Yes. Accepting cryptocurrency changes nothing about licensing — a crypto casino without a checkable licence number is exactly as risky as any other unlicensed site.
Bitcoin and Ethereum almost everywhere, with USDT, Litecoin and Dogecoin common. The list per casino is on its review page.