Regardless as to whether the benefit is deserved or not, the issue is surely, does this suggestion help any. Not sure it does. Those who wish to support themselves and contribute to society will already be trying to get to that stage, whilst those who are not will not be fazed by having a card. They won't see it as a shame thing since they are already prepared to live off of others and probably do not hide that fact.
The thought that those given benefits should be given toil to earn them seems ok at first glance but there are 2 problems at least (off the top of my head). First, if there are tasks they could do then those tasks ought to already form part of paid employment. So there can not be spare tasks available to hand out to claimants. Second is a human dignity issue. One ought not reach a stage where one can say, "You are poor, you have to do anything I tell you because of your lack of worth or I shan't give you any charity". It's not the sort of society most will be wanting; so a sensible balance for these things has to be found.