Yes, I know that, the point is that it removes the impulse element from a potential suicide attempt. Buying a bottle of 100 paracetamol from a single chemist and consuming them in a short period of time is a very different proposition to trudging around several chemists, over an extended period of time, to purchase enough paracetamol to make a serious suicide attempt. It gives pause for thought, and introduces the distinct possibility of a 'second chance' mentality setting in, and ultimately the suicide attempt not being made at all, or the person deciding to call a friend or family member to ask for help. This is a change that literally saved lives.
So it is with online casinos, a player could get dangerously 'in the zone' at a single casino, making big bets, redepositing multiple times, losing track of what and how they're spending. Add the layers of abstraction of depositing at multiple casinos, that 'pause for thought' as to what they're doing, and that same player may well be protected from a gambling binge that could cause them and their families serious financial harm.