online casinos will never provide loan facilities to their customers because that will be very risky because so many customers come from countries that prohibit gambling, so even if they provide credit card guarantees or KYC it is very risky for online casinos.
Even though the online casino has the KYC of the users, yet it is very easy for scammers to create an account, do the KYC, and apply for a loan.
Some can say that casinos can safeguard the return of the loans but not allow the withdrawal until the loan is cleared. How about anyone getting the loan, losing all in the gambling, and quitting the site forever without returning the loan?
it's different from land-based casinos, in that the country or city certainly allows the gambling business, so it's only natural that land-based casinos provide loans to their customers. and I'm not sure if gamblers would avoid the casino if offered a betting loan because we know that not all gamblers are sane minds but many gamblers will accept such an offer.
In physical casinos, it is easier to recover the loans, but it is worth it for the gambling casino to give the loan service and face all these hassles from the gamblers not returning or delaying the return of loans, as they will usually lose all the loan money in the gambling.