Obviously B?

I would argue that you are placing misnamed choices. Both are different flavours of Justice:

A) Retributive Justice: Put them in Jail for long time.

B) Rehabilitative Justice: Put them in medical care for an year till their gambling addiction is cured. Then they are free to integrate back into society.

All else being equal, I would absolutely prefer B over A. However, there is also a third option C, which can be combined with either A or B:

C) Restorative Justice: Require them to do a certain type and amount of work for you or for the state to make up for an agreed amount of your lost money and moral damages.

Give me a mix of B and C any day, and throw A down the drain (in the sense of prison purely as punishment, I have nothing against using prison to protect society from certain criminals).

I know you think this is some hard dilemma that will force people to admit "yes of course I want them punished". But it really isn't. At the end of the day, putting the guy in jail without rehabilitation doesn't help me at all, except quench the thirst for revenge, which is always there of course, but I know giving in to it is like chasing a fix; it'll make me feel better in the short term and like a vindictive asshole in the long term.

What would make me feel better in the long term is knowing that at least something good came out of my losing all my money. In case B as opposed to nothing at all in case A.

Presumably you could have some combo of A and B.