Yes. Maestro isn’t only legal in Canada, but worldwide. It was established in 1991 and has since become a popular payment method accepted everywhere, just like other famous bank cards. Quite a few casinos don’t accept Maestro these days and the method is popular in the USA, Canada, Europe, and Australia. As such, you can use Maestro in Canada without breaking any regulation. The prepaid cards are also legitimate and no law prohibits Maestro’s usage in casinos.