Just like all prohibitions, if you take away access to X, people will just find other (often illegal/dangerous) ways to do X. We can make gambling less convenient and push it back into the backroom poker rooms and illegal bookies who break peoples' legs, but it would be more effective to solve the problems of despair, desperation and hopelessness that are driving people to gambling in the first place. That's a lot harder, so here we are talking about bans.