Yes they do but it will depend on what type of debit card you have. If you have a interac then no that will not work but if you have a visa or mastercard then it is possible it might work. Not saying that it always works as many of these companies do put restrictions on gambling. However there is other ways to fund your casino account using your debit card. This is why the online casinos work together with some webwallets so they can have all the options available to help users purchase.
Your debit card will help you when you set up an account with these places as it can ensure funds are there available but they will also debit your bank if you wish to have higher limits than you start out with. You will have to wait a few days for them to process everything in order to get your account set up, but that is a one time thing as most online casinos will accept these methods so it isn’t like you have to establish yourself at each and every casino. The hassle seems like it takes away from the casinos but it is well worth it after you have done everything you need and in the meantime you can always play casinos for free, or you can wait the days it takes to complete the process.