Obviously there's a risk that some of the money will be "wasted" on booze or tobacco but in practice that looks like much less wastage than the guaranteed waste involved in a high-overhead prescriptive charity.It seems that the cost of "targeting charity" are actually quite high. In general, we don't like to prescribe how people spend money from other sources. I am not sure that it really makes sense to do so in the case of poverty, either, given the surprisingly large costs required to ensure that the aid is spent precisely the way that the giver intended. Now, it is true that earned income would be even better but the only way for a government to accomplish that would be with either monetary policy or a jobs program.
Neither of these seems to be on the table at the moment.