For the fact that we already have several casinos that have gone ahead with the creation of their ecosystem and even their blockchain with the native token to be used as a utility token of the casino, this token is fast and some do not require fees to send them from their host wallets.
Having varieties of altcoins as payment methods helped the stress of waiting and less fees because most of the altcoins give low to zero transaction fees and free networks that process payment within a second.