Do all casinos available on the online gambling market accept Siru Mobile as a payment method?

Unfortunately, no. As mentioned, the method is available in several countries only, and across more than 70 online casinos. So those casinos that offer it as a payment method are usually casinos that accept players from the countries where Siru Mobile is available. Before you choose the casino that offers it to join, check whether the method is available in your country of residence.