A clear reply to "How bitcoin casino works?" starts with two older coins that casino cashiers often list beside Bitcoin, Ethereum and Litecoin, which do quite different jobs. Ethereum runs programs and carries tokens, while Litecoin mostly moves value from one address to another. Knowing how each network charges its fees and what its addresses look like keeps a transfer on the right chain, where a mistake may cost the whole amount. Nothing here is a reason to buy either coin.
A Litecoin wallet works much like a Bitcoin wallet, but the addresses look different. A Litecoin wallet address commonly starts with L, M or ltc1, and most wallets refuse a Bitcoin address in that field, though care is still needed. When Litecoin is withdrawn from an exchange or casino, the right choice is the native Litecoin network rather than a copy of the coin issued on another chain. Sending from a personal wallet means pasting the address, reading the fee and confirming the amount, because a confirmed transaction cannot be reversed.
Litecoin is one of the oldest coins, built on the Bitcoin design with changes that produce blocks about four times as often. On the question of Litecoin vs Bitcoin, Litecoin tends to confirm sooner and to charge lower fees, which is why some casinos accept it for deposits and withdrawals. It runs no smart contracts the way Ethereum does; its job is mainly payments. Its price swings like any unstable coin, so it suits moving value more than keeping it steady. A cashier usually states how many confirmations it needs.
The Ethereum network measures the work behind each transaction in units called gas. Ethereum gas fees are paid in ETH, and the total depends on how much gas an action uses and on the price per unit at that moment, which climbs when the network is congested. A plain transfer needs less gas than a call to a complex contract. Wallets show an estimated fee before anything is confirmed, and on a busy day that fee can exceed a small transfer. A transaction that runs out of gas fails and still pays for the gas it burned.
Further questions
Why does a wallet need ETH to send USDT on Ethereum?
Gas on Ethereum is paid in ETH even when the coin being sent is a token, so a wallet holding only USDT cannot move it.
Which network should a Litecoin withdrawal use?
The native Litecoin network, not a copy of the coin issued on another chain; a coin sent to an address on another chain can be lost.
What decides Ethereum gas fees?
The amount of gas an action uses and the price per unit at that moment, which climbs when the network is crowded.
What does an ETH wallet address look like?
It starts with 0x followed by forty hexadecimal characters, and several compatible chains use the same format, so the address alone does not name the network.