The problem with those jobs is that people capable of doing them are already employed. Welfare is still needed for those who can't.

The pointless job sucks out many hours of productive hobbies and caretaking, space to think, innovate and organise.

This might be the desired effect - one of the means to control the population.

The counter-argument is that these jobs are sucking out many hours of taking drugs (incl. alcohol), watching TV and falling into depression, since many can't really handle being idle.

I tend to be more optimistic and think that the problems arise by our current model of unemployment rather than the idleness by itself, but I can't pretend I know the answer.