Visa Inc, commonly known as Visa, is nothing more than an American multinational financial services corporation from Foster City, California. Its purpose is to facilitate electronic funds transfers worldwide, mostly by using a Visa credit/debit card and gift cards. There is not one online casino in this world which doesn't accept Visa for deposits or cash out.
Qatar is a small country with an attractive shoreline and is renowned for its futuristic architecture and desert-based activities. As Qatar is an Islamic country, all types of gambling are forbidden, with strict penalties imposed. However, the government does not appear to police online betting sites actively, so some form of gambling may be possible.