Not this again...
Look, I'm on the centre-right. I've supported reforming the welfare system to reduce dependency and to improve the impetus into finding work.
But I really do wonder where people get off with this sort of idea. It's positively totalitarian. We give people enough to get by and live a fairly decent life, even if they don't have a job. For the poorest in our society, who live financially from day to day, this does necessitate choices. But we provide more than is required simply for a person to live.
Some people spend benefits on things that others disapprove of - I say "so what?". By the same token, they are having to make savings in other areas of their lives. You mention children - if a person is a terrible parent, whether they're using their child benefit money appropriately will be the least of a child's worries. Indeed, we already do pay a proportion of public funds directly to help in these circumstances, with free school meals and help with school uniform costs etc. These are best administered locally, because they can be provided as part of a package of support that includes intervention from social services to provide help where it is appropriate.
If you really want something to consider, look at personal debt. That is where people are often ending up with significant problems and the end result is that it is taxpayer's money that is (indirectly) keeping those vultures in the payday lending industry afloat - and then having to take action when the borrowers end up destitute too.
We already have record levels of employment in this country. Out-of-work benefits account for only a small proportion of our total social security budget. It seems to me that these inclinations to dole out food stamps - which, incidentally, wouldn't achieve the objective anyway - are less about helping people and more about a mean-spirited assurance that they're somehow not able to derive the simplest pleasures from anything in their lives.