Tough one. I'm a firm believer in drug decriminalisation and personal choice.

However equally I don't want to see welfare (paid for by my tax dollars) to be wasted or used to fund criminal enterprise.
Even moreso where the recipient has kids and drug use is diverting funds away from them.

Same reason why I support the welfare cards not being able to be used for booze or cigarettes.. If its your own money do as you will, if its a handout, use it productively.