If a gambling site owner wants to reach more users, going mobile friendly is a good idea. Not everyone can afford a desktop or a laptop. A user may have a desktop or a laptop but its not all the time that they have access to it. In my case I don't carry my laptop all the time. When I go to work, as much as possible all I want is just a clutch bag with me and not a laptop bag or anything with the same size.
I couldn't agree more, adopting mobile money is a means of reaching out to the masses who hitherto might not be reachable via a website online or on-site at a gambling house. This is a great way of expanding the gambling business and every owner/house might want to reach-out to as many as they can but then the question arises whether it needs to be that way or not and that is where Jurisdiction comes into play; some governments wouldn't care about rampant gambling as they tend to benefit through taxes but any society where morality is of utmost importance would guard against mass gambling in any form.